[sfrench/cifs-2.6.git] / include / drm / drm_crtc.h

/*
 * Copyright © 2006 Keith Packard
 * Copyright © 2007-2008 Dave Airlie
 * Copyright © 2007-2008 Intel Corporation
 *   Jesse Barnes <jesse.barnes@intel.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#ifndef __DRM_CRTC_H__
#define __DRM_CRTC_H__

#include <linux/i2c.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/idr.h>
#include <linux/fb.h>
#include <linux/hdmi.h>
#include <linux/media-bus-format.h>
#include <uapi/drm/drm_mode.h>
#include <uapi/drm/drm_fourcc.h>
#include <drm/drm_modeset_lock.h>
#include <drm/drm_rect.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_modes.h>
#include <drm/drm_connector.h>
#include <drm/drm_encoder.h>

struct drm_device;
struct drm_mode_set;
struct drm_file;
struct drm_clip_rect;
struct device_node;
struct fence;
struct edid;

static inline int64_t U642I64(uint64_t val)
{
        return (int64_t)*((int64_t *)&val);
}
static inline uint64_t I642U64(int64_t val)
{
        return (uint64_t)*((uint64_t *)&val);
}

/*
 * Rotation property bits. DRM_ROTATE_<degrees> rotates the image by the
 * specified amount in degrees in counter clockwise direction. DRM_REFLECT_X and
 * DRM_REFLECT_Y reflects the image along the specified axis prior to rotation
 */
#define DRM_ROTATE_0    BIT(0)
#define DRM_ROTATE_90   BIT(1)
#define DRM_ROTATE_180  BIT(2)
#define DRM_ROTATE_270  BIT(3)
#define DRM_ROTATE_MASK (DRM_ROTATE_0   | DRM_ROTATE_90 | \
                         DRM_ROTATE_180 | DRM_ROTATE_270)
#define DRM_REFLECT_X   BIT(4)
#define DRM_REFLECT_Y   BIT(5)
#define DRM_REFLECT_MASK (DRM_REFLECT_X | DRM_REFLECT_Y)

/* data corresponds to displayid vend/prod/serial */
struct drm_tile_group {
        struct kref refcount;
        struct drm_device *dev;
        int id;
        u8 group_data[8];
};

struct drm_property_blob {
        struct drm_mode_object base;
        struct drm_device *dev;
        struct list_head head_global;
        struct list_head head_file;
        size_t length;
        unsigned char data[];
};

struct drm_property_enum {
        uint64_t value;
        struct list_head head;
        char name[DRM_PROP_NAME_LEN];
};

struct drm_property {
        struct list_head head;
        struct drm_mode_object base;
        uint32_t flags;
        char name[DRM_PROP_NAME_LEN];
        uint32_t num_values;
        uint64_t *values;
        struct drm_device *dev;

        struct list_head enum_list;
};

struct drm_crtc;
struct drm_encoder;
struct drm_pending_vblank_event;
struct drm_plane;
struct drm_bridge;
struct drm_atomic_state;

struct drm_crtc_helper_funcs;
struct drm_encoder_helper_funcs;
struct drm_plane_helper_funcs;

/**
 * struct drm_crtc_state - mutable CRTC state
 * @crtc: backpointer to the CRTC
 * @enable: whether the CRTC should be enabled, gates all other state
 * @active: whether the CRTC is actively displaying (used for DPMS)
 * @planes_changed: planes on this crtc are updated
 * @mode_changed: crtc_state->mode or crtc_state->enable has been changed
 * @active_changed: crtc_state->active has been toggled.
 * @connectors_changed: connectors to this crtc have been updated
 * @zpos_changed: zpos values of planes on this crtc have been updated
 * @color_mgmt_changed: color management properties have changed (degamma or
 *      gamma LUT or CSC matrix)
 * @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes
 * @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors
 * @encoder_mask: bitmask of (1 << drm_encoder_index(encoder)) of attached encoders
 * @last_vblank_count: for helpers and drivers to capture the vblank of the
 *      update to ensure framebuffer cleanup isn't done too early
 * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
 * @mode: current mode timings
 * @mode_blob: &drm_property_blob for @mode
 * @degamma_lut: Lookup table for converting framebuffer pixel data
 *      before apply the conversion matrix
 * @ctm: Transformation matrix
 * @gamma_lut: Lookup table for converting pixel data after the
 *      conversion matrix
 * @event: optional pointer to a DRM event to signal upon completion of the
 *      state update
 * @state: backpointer to global drm_atomic_state
 *
 * Note that the distinction between @enable and @active is rather subtile:
 * Flipping @active while @enable is set without changing anything else may
 * never return in a failure from the ->atomic_check callback. Userspace assumes
 * that a DPMS On will always succeed. In other words: @enable controls resource
 * assignment, @active controls the actual hardware state.
 */
struct drm_crtc_state {
        struct drm_crtc *crtc;

        bool enable;
        bool active;

        /* computed state bits used by helpers and drivers */
        bool planes_changed : 1;
        bool mode_changed : 1;
        bool active_changed : 1;
        bool connectors_changed : 1;
        bool zpos_changed : 1;
        bool color_mgmt_changed : 1;

        /* attached planes bitmask:
         * WARNING: transitional helpers do not maintain plane_mask so
         * drivers not converted over to atomic helpers should not rely
         * on plane_mask being accurate!
         */
        u32 plane_mask;

        u32 connector_mask;
        u32 encoder_mask;

        /* last_vblank_count: for vblank waits before cleanup */
        u32 last_vblank_count;

        /* adjusted_mode: for use by helpers and drivers */
        struct drm_display_mode adjusted_mode;

        struct drm_display_mode mode;

        /* blob property to expose current mode to atomic userspace */
        struct drm_property_blob *mode_blob;

        /* blob property to expose color management to userspace */
        struct drm_property_blob *degamma_lut;
        struct drm_property_blob *ctm;
        struct drm_property_blob *gamma_lut;

        struct drm_pending_vblank_event *event;

        struct drm_atomic_state *state;
};

/**
 * struct drm_crtc_funcs - control CRTCs for a given device
 *
 * The drm_crtc_funcs structure is the central CRTC management structure
 * in the DRM.  Each CRTC controls one or more connectors (note that the name
 * CRTC is simply historical, a CRTC may control LVDS, VGA, DVI, TV out, etc.
 * connectors, not just CRTs).
 *
 * Each driver is responsible for filling out this structure at startup time,
 * in addition to providing other modesetting features, like i2c and DDC
 * bus accessors.
 */
struct drm_crtc_funcs {
        /**
         * @reset:
         *
         * Reset CRTC hardware and software state to off. This function isn't
         * called by the core directly, only through drm_mode_config_reset().
         * It's not a helper hook only for historical reasons.
         *
         * Atomic drivers can use drm_atomic_helper_crtc_reset() to reset
         * atomic state using this hook.
         */
        void (*reset)(struct drm_crtc *crtc);

        /**
         * @cursor_set:
         *
         * Update the cursor image. The cursor position is relative to the CRTC
         * and can be partially or fully outside of the visible area.
         *
         * Note that contrary to all other KMS functions the legacy cursor entry
         * points don't take a framebuffer object, but instead take directly a
         * raw buffer object id from the driver's buffer manager (which is
         * either GEM or TTM for current drivers).
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_set)(struct drm_crtc *crtc, struct drm_file *file_priv,
                          uint32_t handle, uint32_t width, uint32_t height);

        /**
         * @cursor_set2:
         *
         * Update the cursor image, including hotspot information. The hotspot
         * must not affect the cursor position in CRTC coordinates, but is only
         * meant as a hint for virtualized display hardware to coordinate the
         * guests and hosts cursor position. The cursor hotspot is relative to
         * the cursor image. Otherwise this works exactly like @cursor_set.
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_set2)(struct drm_crtc *crtc, struct drm_file *file_priv,
                           uint32_t handle, uint32_t width, uint32_t height,
                           int32_t hot_x, int32_t hot_y);

        /**
         * @cursor_move:
         *
         * Update the cursor position. The cursor does not need to be visible
         * when this hook is called.
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_move)(struct drm_crtc *crtc, int x, int y);

        /**
         * @gamma_set:
         *
         * Set gamma on the CRTC.
         *
         * This callback is optional.
         *
         * NOTE:
         *
         * Drivers that support gamma tables and also fbdev emulation through
         * the provided helper library need to take care to fill out the gamma
         * hooks for both. Currently there's a bit an unfortunate duplication
         * going on, which should eventually be unified to just one set of
         * hooks.
         */
        int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
                         uint32_t size);

        /**
         * @destroy:
         *
         * Clean up plane resources. This is only called at driver unload time
         * through drm_mode_config_cleanup() since a CRTC cannot be hotplugged
         * in DRM.
         */
        void (*destroy)(struct drm_crtc *crtc);

        /**
         * @set_config:
         *
         * This is the main legacy entry point to change the modeset state on a
         * CRTC. All the details of the desired configuration are passed in a
         * struct &drm_mode_set - see there for details.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_set_config() to implement this hook.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_config)(struct drm_mode_set *set);

        /**
         * @page_flip:
         *
         * Legacy entry point to schedule a flip to the given framebuffer.
         *
         * Page flipping is a synchronization mechanism that replaces the frame
         * buffer being scanned out by the CRTC with a new frame buffer during
         * vertical blanking, avoiding tearing (except when requested otherwise
         * through the DRM_MODE_PAGE_FLIP_ASYNC flag). When an application
         * requests a page flip the DRM core verifies that the new frame buffer
         * is large enough to be scanned out by the CRTC in the currently
         * configured mode and then calls the CRTC ->page_flip() operation with a
         * pointer to the new frame buffer.
         *
         * The driver must wait for any pending rendering to the new framebuffer
         * to complete before executing the flip. It should also wait for any
         * pending rendering from other drivers if the underlying buffer is a
         * shared dma-buf.
         *
         * An application can request to be notified when the page flip has
         * completed. The drm core will supply a struct &drm_event in the event
         * parameter in this case. This can be handled by the
         * drm_crtc_send_vblank_event() function, which the driver should call on
         * the provided event upon completion of the flip. Note that if
         * the driver supports vblank signalling and timestamping the vblank
         * counters and timestamps must agree with the ones returned from page
         * flip events. With the current vblank helper infrastructure this can
         * be achieved by holding a vblank reference while the page flip is
         * pending, acquired through drm_crtc_vblank_get() and released with
         * drm_crtc_vblank_put(). Drivers are free to implement their own vblank
         * counter and timestamp tracking though, e.g. if they have accurate
         * timestamp registers in hardware.
         *
         * This callback is optional.
         *
         * NOTE:
         *
         * Very early versions of the KMS ABI mandated that the driver must
         * block (but not reject) any rendering to the old framebuffer until the
         * flip operation has completed and the old framebuffer is no longer
         * visible. This requirement has been lifted, and userspace is instead
         * expected to request delivery of an event and wait with recycling old
         * buffers until such has been received.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure. Note that if a
         * ->page_flip() operation is already pending the callback should return
         * -EBUSY. Pageflips on a disabled CRTC (either by setting a NULL mode
         * or just runtime disabled through DPMS respectively the new atomic
         * "ACTIVE" state) should result in an -EINVAL error code. Note that
         * drm_atomic_helper_page_flip() checks this already for atomic drivers.
         */
        int (*page_flip)(struct drm_crtc *crtc,
                         struct drm_framebuffer *fb,
                         struct drm_pending_vblank_event *event,
                         uint32_t flags);

        /**
         * @set_property:
         *
         * This is the legacy entry point to update a property attached to the
         * CRTC.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_crtc_set_property() to implement this hook.
         *
         * This callback is optional if the driver does not support any legacy
         * driver-private properties.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_property)(struct drm_crtc *crtc,
                            struct drm_property *property, uint64_t val);

        /**
         * @atomic_duplicate_state:
         *
         * Duplicate the current atomic state for this CRTC and return it.
         * The core and helpers gurantee that any atomic state duplicated with
         * this hook and still owned by the caller (i.e. not transferred to the
         * driver by calling ->atomic_commit() from struct
         * &drm_mode_config_funcs) will be cleaned up by calling the
         * @atomic_destroy_state hook in this structure.
         *
         * Atomic drivers which don't subclass struct &drm_crtc should use
         * drm_atomic_helper_crtc_duplicate_state(). Drivers that subclass the
         * state structure to extend it with driver-private state should use
         * __drm_atomic_helper_crtc_duplicate_state() to make sure shared state is
         * duplicated in a consistent fashion across drivers.
         *
         * It is an error to call this hook before crtc->state has been
         * initialized correctly.
         *
         * NOTE:
         *
         * If the duplicate state references refcounted resources this hook must
         * acquire a reference for each of them. The driver must release these
         * references again in @atomic_destroy_state.
         *
         * RETURNS:
         *
         * Duplicated atomic state or NULL when the allocation failed.
         */
        struct drm_crtc_state *(*atomic_duplicate_state)(struct drm_crtc *crtc);

        /**
         * @atomic_destroy_state:
         *
         * Destroy a state duplicated with @atomic_duplicate_state and release
         * or unreference all resources it references
         */
        void (*atomic_destroy_state)(struct drm_crtc *crtc,
                                     struct drm_crtc_state *state);

        /**
         * @atomic_set_property:
         *
         * Decode a driver-private property value and store the decoded value
         * into the passed-in state structure. Since the atomic core decodes all
         * standardized properties (even for extensions beyond the core set of
         * properties which might not be implemented by all drivers) this
         * requires drivers to subclass the state structure.
         *
         * Such driver-private properties should really only be implemented for
         * truly hardware/vendor specific state. Instead it is preferred to
         * standardize atomic extension and decode the properties used to expose
         * such an extension in the core.
         *
         * Do not call this function directly, use
         * drm_atomic_crtc_set_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * NOTE:
         *
         * This function is called in the state assembly phase of atomic
         * modesets, which can be aborted for any reason (including on
         * userspace's request to just check whether a configuration would be
         * possible). Drivers MUST NOT touch any persistent state (hardware or
         * software) or data structures except the passed in @state parameter.
         *
         * Also since userspace controls in which order properties are set this
         * function must not do any input validation (since the state update is
         * incomplete and hence likely inconsistent). Instead any such input
         * validation must be done in the various atomic_check callbacks.
         *
         * RETURNS:
         *
         * 0 if the property has been found, -EINVAL if the property isn't
         * implemented by the driver (which should never happen, the core only
         * asks for properties attached to this CRTC). No other validation is
         * allowed by the driver. The core already checks that the property
         * value is within the range (integer, valid enum value, ...) the driver
         * set when registering the property.
         */
        int (*atomic_set_property)(struct drm_crtc *crtc,
                                   struct drm_crtc_state *state,
                                   struct drm_property *property,
                                   uint64_t val);
        /**
         * @atomic_get_property:
         *
         * Reads out the decoded driver-private property. This is used to
         * implement the GETCRTC IOCTL.
         *
         * Do not call this function directly, use
         * drm_atomic_crtc_get_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * RETURNS:
         *
         * 0 on success, -EINVAL if the property isn't implemented by the
         * driver (which should never happen, the core only asks for
         * properties attached to this CRTC).
         */
        int (*atomic_get_property)(struct drm_crtc *crtc,
                                   const struct drm_crtc_state *state,
                                   struct drm_property *property,
                                   uint64_t *val);

        /**
         * @late_register:
         *
         * This optional hook can be used to register additional userspace
         * interfaces attached to the crtc like debugfs interfaces.
         * It is called late in the driver load sequence from drm_dev_register().
         * Everything added from this callback should be unregistered in
         * the early_unregister callback.
         *
         * Returns:
         *
         * 0 on success, or a negative error code on failure.
         */
        int (*late_register)(struct drm_crtc *crtc);

        /**
         * @early_unregister:
         *
         * This optional hook should be used to unregister the additional
         * userspace interfaces attached to the crtc from
         * late_unregister(). It is called from drm_dev_unregister(),
         * early in the driver unload sequence to disable userspace access
         * before data structures are torndown.
         */
        void (*early_unregister)(struct drm_crtc *crtc);
};

/**
 * struct drm_crtc - central CRTC control structure
 * @dev: parent DRM device
 * @port: OF node used by drm_of_find_possible_crtcs()
 * @head: list management
 * @name: human readable name, can be overwritten by the driver
 * @mutex: per-CRTC locking
 * @base: base KMS object for ID tracking etc.
 * @primary: primary plane for this CRTC
 * @cursor: cursor plane for this CRTC
 * @cursor_x: current x position of the cursor, used for universal cursor planes
 * @cursor_y: current y position of the cursor, used for universal cursor planes
 * @enabled: is this CRTC enabled?
 * @mode: current mode timings
 * @hwmode: mode timings as programmed to hw regs
 * @x: x position on screen
 * @y: y position on screen
 * @funcs: CRTC control functions
 * @gamma_size: size of gamma ramp
 * @gamma_store: gamma ramp values
 * @helper_private: mid-layer private data
 * @properties: property tracking for this CRTC
 *
 * Each CRTC may have one or more connectors associated with it.  This structure
 * allows the CRTC to be controlled.
 */
struct drm_crtc {
        struct drm_device *dev;
        struct device_node *port;
        struct list_head head;

        char *name;

        /**
         * @mutex:
         *
         * This provides a read lock for the overall crtc state (mode, dpms
         * state, ...) and a write lock for everything which can be update
         * without a full modeset (fb, cursor data, crtc properties ...). Full
         * modeset also need to grab dev->mode_config.connection_mutex.
         */
        struct drm_modeset_lock mutex;

        struct drm_mode_object base;

        /* primary and cursor planes for CRTC */
        struct drm_plane *primary;
        struct drm_plane *cursor;

        /**
         * @index: Position inside the mode_config.list, can be used as an array
         * index. It is invariant over the lifetime of the CRTC.
         */
        unsigned index;

        /* position of cursor plane on crtc */
        int cursor_x;
        int cursor_y;

        bool enabled;

        /* Requested mode from modesetting. */
        struct drm_display_mode mode;

        /* Programmed mode in hw, after adjustments for encoders,
         * crtc, panel scaling etc. Needed for timestamping etc.
         */
        struct drm_display_mode hwmode;

        int x, y;
        const struct drm_crtc_funcs *funcs;

        /* Legacy FB CRTC gamma size for reporting to userspace */
        uint32_t gamma_size;
        uint16_t *gamma_store;

        /* if you are using the helper */
        const struct drm_crtc_helper_funcs *helper_private;

        struct drm_object_properties properties;

        /**
         * @state:
         *
         * Current atomic state for this CRTC.
         */
        struct drm_crtc_state *state;

        /**
         * @commit_list:
         *
         * List of &drm_crtc_commit structures tracking pending commits.
         * Protected by @commit_lock. This list doesn't hold its own full
         * reference, but burrows it from the ongoing commit. Commit entries
         * must be removed from this list once the commit is fully completed,
         * but before it's correspoding &drm_atomic_state gets destroyed.
         */
        struct list_head commit_list;

        /**
         * @commit_lock:
         *
         * Spinlock to protect @commit_list.
         */
        spinlock_t commit_lock;

        /**
         * @acquire_ctx:
         *
         * Per-CRTC implicit acquire context used by atomic drivers for legacy
         * IOCTLs, so that atomic drivers can get at the locking acquire
         * context.
         */
        struct drm_modeset_acquire_ctx *acquire_ctx;
};

/**
 * struct drm_plane_state - mutable plane state
 * @plane: backpointer to the plane
 * @crtc: currently bound CRTC, NULL if disabled
 * @fb: currently bound framebuffer
 * @fence: optional fence to wait for before scanning out @fb
 * @crtc_x: left position of visible portion of plane on crtc
 * @crtc_y: upper position of visible portion of plane on crtc
 * @crtc_w: width of visible portion of plane on crtc
 * @crtc_h: height of visible portion of plane on crtc
 * @src_x: left position of visible portion of plane within
 *      plane (in 16.16)
 * @src_y: upper position of visible portion of plane within
 *      plane (in 16.16)
 * @src_w: width of visible portion of plane (in 16.16)
 * @src_h: height of visible portion of plane (in 16.16)
 * @rotation: rotation of the plane
 * @zpos: priority of the given plane on crtc (optional)
 * @normalized_zpos: normalized value of zpos: unique, range from 0 to N-1
 *      where N is the number of active planes for given crtc
 * @src: clipped source coordinates of the plane (in 16.16)
 * @dst: clipped destination coordinates of the plane
 * @visible: visibility of the plane
 * @state: backpointer to global drm_atomic_state
 */
struct drm_plane_state {
        struct drm_plane *plane;

        struct drm_crtc *crtc;   /* do not write directly, use drm_atomic_set_crtc_for_plane() */
        struct drm_framebuffer *fb;  /* do not write directly, use drm_atomic_set_fb_for_plane() */
        struct fence *fence;

        /* Signed dest location allows it to be partially off screen */
        int32_t crtc_x, crtc_y;
        uint32_t crtc_w, crtc_h;

        /* Source values are 16.16 fixed point */
        uint32_t src_x, src_y;
        uint32_t src_h, src_w;

        /* Plane rotation */
        unsigned int rotation;

        /* Plane zpos */
        unsigned int zpos;
        unsigned int normalized_zpos;

        /* Clipped coordinates */
        struct drm_rect src, dst;

        /*
         * Is the plane actually visible? Can be false even
         * if fb!=NULL and crtc!=NULL, due to clipping.
         */
        bool visible;

        struct drm_atomic_state *state;
};


/**
 * struct drm_plane_funcs - driver plane control functions
 */
struct drm_plane_funcs {
        /**
         * @update_plane:
         *
         * This is the legacy entry point to enable and configure the plane for
         * the given CRTC and framebuffer. It is never called to disable the
         * plane, i.e. the passed-in crtc and fb paramters are never NULL.
         *
         * The source rectangle in frame buffer memory coordinates is given by
         * the src_x, src_y, src_w and src_h parameters (as 16.16 fixed point
         * values). Devices that don't support subpixel plane coordinates can
         * ignore the fractional part.
         *
         * The destination rectangle in CRTC coordinates is given by the
         * crtc_x, crtc_y, crtc_w and crtc_h parameters (as integer values).
         * Devices scale the source rectangle to the destination rectangle. If
         * scaling is not supported, and the source rectangle size doesn't match
         * the destination rectangle size, the driver must return a
         * -<errorname>EINVAL</errorname> error.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_update_plane() to implement this hook.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*update_plane)(struct drm_plane *plane,
                            struct drm_crtc *crtc, struct drm_framebuffer *fb,
                            int crtc_x, int crtc_y,
                            unsigned int crtc_w, unsigned int crtc_h,
                            uint32_t src_x, uint32_t src_y,
                            uint32_t src_w, uint32_t src_h);

        /**
         * @disable_plane:
         *
         * This is the legacy entry point to disable the plane. The DRM core
         * calls this method in response to a DRM_IOCTL_MODE_SETPLANE IOCTL call
         * with the frame buffer ID set to 0.  Disabled planes must not be
         * processed by the CRTC.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_disable_plane() to implement this hook.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*disable_plane)(struct drm_plane *plane);

        /**
         * @destroy:
         *
         * Clean up plane resources. This is only called at driver unload time
         * through drm_mode_config_cleanup() since a plane cannot be hotplugged
         * in DRM.
         */
        void (*destroy)(struct drm_plane *plane);

        /**
         * @reset:
         *
         * Reset plane hardware and software state to off. This function isn't
         * called by the core directly, only through drm_mode_config_reset().
         * It's not a helper hook only for historical reasons.
         *
         * Atomic drivers can use drm_atomic_helper_plane_reset() to reset
         * atomic state using this hook.
         */
        void (*reset)(struct drm_plane *plane);

        /**
         * @set_property:
         *
         * This is the legacy entry point to update a property attached to the
         * plane.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_plane_set_property() to implement this hook.
         *
         * This callback is optional if the driver does not support any legacy
         * driver-private properties.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_property)(struct drm_plane *plane,
                            struct drm_property *property, uint64_t val);

        /**
         * @atomic_duplicate_state:
         *
         * Duplicate the current atomic state for this plane and return it.
         * The core and helpers gurantee that any atomic state duplicated with
         * this hook and still owned by the caller (i.e. not transferred to the
         * driver by calling ->atomic_commit() from struct
         * &drm_mode_config_funcs) will be cleaned up by calling the
         * @atomic_destroy_state hook in this structure.
         *
         * Atomic drivers which don't subclass struct &drm_plane_state should use
         * drm_atomic_helper_plane_duplicate_state(). Drivers that subclass the
         * state structure to extend it with driver-private state should use
         * __drm_atomic_helper_plane_duplicate_state() to make sure shared state is
         * duplicated in a consistent fashion across drivers.
         *
         * It is an error to call this hook before plane->state has been
         * initialized correctly.
         *
         * NOTE:
         *
         * If the duplicate state references refcounted resources this hook must
         * acquire a reference for each of them. The driver must release these
         * references again in @atomic_destroy_state.
         *
         * RETURNS:
         *
         * Duplicated atomic state or NULL when the allocation failed.
         */
        struct drm_plane_state *(*atomic_duplicate_state)(struct drm_plane *plane);

        /**
         * @atomic_destroy_state:
         *
         * Destroy a state duplicated with @atomic_duplicate_state and release
         * or unreference all resources it references
         */
        void (*atomic_destroy_state)(struct drm_plane *plane,
                                     struct drm_plane_state *state);

        /**
         * @atomic_set_property:
         *
         * Decode a driver-private property value and store the decoded value
         * into the passed-in state structure. Since the atomic core decodes all
         * standardized properties (even for extensions beyond the core set of
         * properties which might not be implemented by all drivers) this
         * requires drivers to subclass the state structure.
         *
         * Such driver-private properties should really only be implemented for
         * truly hardware/vendor specific state. Instead it is preferred to
         * standardize atomic extension and decode the properties used to expose
         * such an extension in the core.
         *
         * Do not call this function directly, use
         * drm_atomic_plane_set_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * NOTE:
         *
         * This function is called in the state assembly phase of atomic
         * modesets, which can be aborted for any reason (including on
         * userspace's request to just check whether a configuration would be
         * possible). Drivers MUST NOT touch any persistent state (hardware or
         * software) or data structures except the passed in @state parameter.
         *
         * Also since userspace controls in which order properties are set this
         * function must not do any input validation (since the state update is
         * incomplete and hence likely inconsistent). Instead any such input
         * validation must be done in the various atomic_check callbacks.
         *
         * RETURNS:
         *
         * 0 if the property has been found, -EINVAL if the property isn't
         * implemented by the driver (which shouldn't ever happen, the core only
         * asks for properties attached to this plane). No other validation is
         * allowed by the driver. The core already checks that the property
         * value is within the range (integer, valid enum value, ...) the driver
         * set when registering the property.
         */
        int (*atomic_set_property)(struct drm_plane *plane,
                                   struct drm_plane_state *state,
                                   struct drm_property *property,
                                   uint64_t val);

        /**
         * @atomic_get_property:
         *
         * Reads out the decoded driver-private property. This is used to
         * implement the GETPLANE IOCTL.
         *
         * Do not call this function directly, use
         * drm_atomic_plane_get_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * RETURNS:
         *
         * 0 on success, -EINVAL if the property isn't implemented by the
         * driver (which should never happen, the core only asks for
         * properties attached to this plane).
         */
        int (*atomic_get_property)(struct drm_plane *plane,
                                   const struct drm_plane_state *state,
                                   struct drm_property *property,
                                   uint64_t *val);
        /**
         * @late_register:
         *
         * This optional hook can be used to register additional userspace
         * interfaces attached to the plane like debugfs interfaces.
         * It is called late in the driver load sequence from drm_dev_register().
         * Everything added from this callback should be unregistered in
         * the early_unregister callback.
         *
         * Returns:
         *
         * 0 on success, or a negative error code on failure.
         */
        int (*late_register)(struct drm_plane *plane);

        /**
         * @early_unregister:
         *
         * This optional hook should be used to unregister the additional
         * userspace interfaces attached to the plane from
         * late_unregister(). It is called from drm_dev_unregister(),
         * early in the driver unload sequence to disable userspace access
         * before data structures are torndown.
         */
        void (*early_unregister)(struct drm_plane *plane);
};

enum drm_plane_type {
        DRM_PLANE_TYPE_OVERLAY,
        DRM_PLANE_TYPE_PRIMARY,
        DRM_PLANE_TYPE_CURSOR,
};


/**
 * struct drm_plane - central DRM plane control structure
 * @dev: DRM device this plane belongs to
 * @head: for list management
 * @name: human readable name, can be overwritten by the driver
 * @base: base mode object
 * @possible_crtcs: pipes this plane can be bound to
 * @format_types: array of formats supported by this plane
 * @format_count: number of formats supported
 * @format_default: driver hasn't supplied supported formats for the plane
 * @crtc: currently bound CRTC
 * @fb: currently bound fb
 * @old_fb: Temporary tracking of the old fb while a modeset is ongoing. Used by
 *      drm_mode_set_config_internal() to implement correct refcounting.
 * @funcs: helper functions
 * @properties: property tracking for this plane
 * @type: type of plane (overlay, primary, cursor)
 * @state: current atomic state for this plane
 * @zpos_property: zpos property for this plane
 * @helper_private: mid-layer private data
 */
struct drm_plane {
        struct drm_device *dev;
        struct list_head head;

        char *name;

        /**
         * @mutex:
         *
         * Protects modeset plane state, together with the mutex of &drm_crtc
         * this plane is linked to (when active, getting actived or getting
         * disabled).
         */
        struct drm_modeset_lock mutex;

        struct drm_mode_object base;

        uint32_t possible_crtcs;
        uint32_t *format_types;
        unsigned int format_count;
        bool format_default;

        struct drm_crtc *crtc;
        struct drm_framebuffer *fb;

        struct drm_framebuffer *old_fb;

        const struct drm_plane_funcs *funcs;

        struct drm_object_properties properties;

        enum drm_plane_type type;

        /**
         * @index: Position inside the mode_config.list, can be used as an array
         * index. It is invariant over the lifetime of the plane.
         */
        unsigned index;

        const struct drm_plane_helper_funcs *helper_private;

        struct drm_plane_state *state;

        struct drm_property *zpos_property;
};

/**
 * struct drm_bridge_funcs - drm_bridge control functions
 */
struct drm_bridge_funcs {
        /**
         * @attach:
         *
         * This callback is invoked whenever our bridge is being attached to a
         * &drm_encoder.
         *
         * The attach callback is optional.
         *
         * RETURNS:
         *
         * Zero on success, error code on failure.
         */
        int (*attach)(struct drm_bridge *bridge);

        /**
         * @detach:
         *
         * This callback is invoked whenever our bridge is being detached from a
         * &drm_encoder.
         *
         * The detach callback is optional.
         */
        void (*detach)(struct drm_bridge *bridge);

        /**
         * @mode_fixup:
         *
         * This callback is used to validate and adjust a mode. The paramater
         * mode is the display mode that should be fed to the next element in
         * the display chain, either the final &drm_connector or the next
         * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
         * requires. It can be modified by this callback and does not need to
         * match mode.
         *
         * This is the only hook that allows a bridge to reject a modeset. If
         * this function passes all other callbacks must succeed for this
         * configuration.
         *
         * The mode_fixup callback is optional.
         *
         * NOTE:
         *
         * This function is called in the check phase of atomic modesets, which
         * can be aborted for any reason (including on userspace's request to
         * just check whether a configuration would be possible). Drivers MUST
         * NOT touch any persistent state (hardware or software) or data
         * structures except the passed in @state parameter.
         *
         * RETURNS:
         *
         * True if an acceptable configuration is possible, false if the modeset
         * operation should be rejected.
         */
        bool (*mode_fixup)(struct drm_bridge *bridge,
                           const struct drm_display_mode *mode,
                           struct drm_display_mode *adjusted_mode);
        /**
         * @disable:
         *
         * This callback should disable the bridge. It is called right before
         * the preceding element in the display pipe is disabled. If the
         * preceding element is a bridge this means it's called before that
         * bridge's ->disable() function. If the preceding element is a
         * &drm_encoder it's called right before the encoder's ->disable(),
         * ->prepare() or ->dpms() hook from struct &drm_encoder_helper_funcs.
         *
         * The bridge can assume that the display pipe (i.e. clocks and timing
         * signals) feeding it is still running when this callback is called.
         *
         * The disable callback is optional.
         */
        void (*disable)(struct drm_bridge *bridge);

        /**
         * @post_disable:
         *
         * This callback should disable the bridge. It is called right after
         * the preceding element in the display pipe is disabled. If the
         * preceding element is a bridge this means it's called after that
         * bridge's ->post_disable() function. If the preceding element is a
         * &drm_encoder it's called right after the encoder's ->disable(),
         * ->prepare() or ->dpms() hook from struct &drm_encoder_helper_funcs.
         *
         * The bridge must assume that the display pipe (i.e. clocks and timing
         * singals) feeding it is no longer running when this callback is
         * called.
         *
         * The post_disable callback is optional.
         */
        void (*post_disable)(struct drm_bridge *bridge);

        /**
         * @mode_set:
         *
         * This callback should set the given mode on the bridge. It is called
         * after the ->mode_set() callback for the preceding element in the
         * display pipeline has been called already. The display pipe (i.e.
         * clocks and timing signals) is off when this function is called.
         */
        void (*mode_set)(struct drm_bridge *bridge,
                         struct drm_display_mode *mode,
                         struct drm_display_mode *adjusted_mode);
        /**
         * @pre_enable:
         *
         * This callback should enable the bridge. It is called right before
         * the preceding element in the display pipe is enabled. If the
         * preceding element is a bridge this means it's called before that
         * bridge's ->pre_enable() function. If the preceding element is a
         * &drm_encoder it's called right before the encoder's ->enable(),
         * ->commit() or ->dpms() hook from struct &drm_encoder_helper_funcs.
         *
         * The display pipe (i.e. clocks and timing signals) feeding this bridge
         * will not yet be running when this callback is called. The bridge must
         * not enable the display link feeding the next bridge in the chain (if
         * there is one) when this callback is called.
         *
         * The pre_enable callback is optional.
         */
        void (*pre_enable)(struct drm_bridge *bridge);

        /**
         * @enable:
         *
         * This callback should enable the bridge. It is called right after
         * the preceding element in the display pipe is enabled. If the
         * preceding element is a bridge this means it's called after that
         * bridge's ->enable() function. If the preceding element is a
         * &drm_encoder it's called right after the encoder's ->enable(),
         * ->commit() or ->dpms() hook from struct &drm_encoder_helper_funcs.
         *
         * The bridge can assume that the display pipe (i.e. clocks and timing
         * signals) feeding it is running when this callback is called. This
         * callback must enable the display link feeding the next bridge in the
         * chain if there is one.
         *
         * The enable callback is optional.
         */
        void (*enable)(struct drm_bridge *bridge);
};

/**
 * struct drm_bridge - central DRM bridge control structure
 * @dev: DRM device this bridge belongs to
 * @encoder: encoder to which this bridge is connected
 * @next: the next bridge in the encoder chain
 * @of_node: device node pointer to the bridge
 * @list: to keep track of all added bridges
 * @funcs: control functions
 * @driver_private: pointer to the bridge driver's internal context
 */
struct drm_bridge {
        struct drm_device *dev;
        struct drm_encoder *encoder;
        struct drm_bridge *next;
#ifdef CONFIG_OF
        struct device_node *of_node;
#endif
        struct list_head list;

        const struct drm_bridge_funcs *funcs;
        void *driver_private;
};

/**
 * struct drm_crtc_commit - track modeset commits on a CRTC
 *
 * This structure is used to track pending modeset changes and atomic commit on
 * a per-CRTC basis. Since updating the list should never block this structure
 * is reference counted to allow waiters to safely wait on an event to complete,
 * without holding any locks.
 *
 * It has 3 different events in total to allow a fine-grained synchronization
 * between outstanding updates::
 *
 *      atomic commit thread                    hardware
 *
 *      write new state into hardware   ---->   ...
 *      signal hw_done
 *                                              switch to new state on next
 *      ...                                     v/hblank
 *
 *      wait for buffers to show up             ...
 *
 *      ...                                     send completion irq
 *                                              irq handler signals flip_done
 *      cleanup old buffers
 *
 *      signal cleanup_done
 *
 *      wait for flip_done              <----
 *      clean up atomic state
 *
 * The important bit to know is that cleanup_done is the terminal event, but the
 * ordering between flip_done and hw_done is entirely up to the specific driver
 * and modeset state change.
 *
 * For an implementation of how to use this look at
 * drm_atomic_helper_setup_commit() from the atomic helper library.
 */
struct drm_crtc_commit {
        /**
         * @crtc:
         *
         * DRM CRTC for this commit.
         */
        struct drm_crtc *crtc;

        /**
         * @ref:
         *
         * Reference count for this structure. Needed to allow blocking on
         * completions without the risk of the completion disappearing
         * meanwhile.
         */
        struct kref ref;

        /**
         * @flip_done:
         *
         * Will be signaled when the hardware has flipped to the new set of
         * buffers. Signals at the same time as when the drm event for this
         * commit is sent to userspace, or when an out-fence is singalled. Note
         * that for most hardware, in most cases this happens after @hw_done is
         * signalled.
         */
        struct completion flip_done;

        /**
         * @hw_done:
         *
         * Will be signalled when all hw register changes for this commit have
         * been written out. Especially when disabling a pipe this can be much
         * later than than @flip_done, since that can signal already when the
         * screen goes black, whereas to fully shut down a pipe more register
         * I/O is required.
         *
         * Note that this does not need to include separately reference-counted
         * resources like backing storage buffer pinning, or runtime pm
         * management.
         */
        struct completion hw_done;

        /**
         * @cleanup_done:
         *
         * Will be signalled after old buffers have been cleaned up by calling
         * drm_atomic_helper_cleanup_planes(). Since this can only happen after
         * a vblank wait completed it might be a bit later. This completion is
         * useful to throttle updates and avoid hardware updates getting ahead
         * of the buffer cleanup too much.
         */
        struct completion cleanup_done;

        /**
         * @commit_entry:
         *
         * Entry on the per-CRTC commit_list. Protected by crtc->commit_lock.
         */
        struct list_head commit_entry;

        /**
         * @event:
         *
         * &drm_pending_vblank_event pointer to clean up private events.
         */
        struct drm_pending_vblank_event *event;
};

struct __drm_planes_state {
        struct drm_plane *ptr;
        struct drm_plane_state *state;
};

struct __drm_crtcs_state {
        struct drm_crtc *ptr;
        struct drm_crtc_state *state;
        struct drm_crtc_commit *commit;
};

struct __drm_connnectors_state {
        struct drm_connector *ptr;
        struct drm_connector_state *state;
};

/**
 * struct drm_atomic_state - the global state object for atomic updates
 * @dev: parent DRM device
 * @allow_modeset: allow full modeset
 * @legacy_cursor_update: hint to enforce legacy cursor IOCTL semantics
 * @legacy_set_config: Disable conflicting encoders instead of failing with -EINVAL.
 * @planes: pointer to array of structures with per-plane data
 * @crtcs: pointer to array of CRTC pointers
 * @num_connector: size of the @connectors and @connector_states arrays
 * @connectors: pointer to array of structures with per-connector data
 * @acquire_ctx: acquire context for this atomic modeset state update
 */
struct drm_atomic_state {
        struct drm_device *dev;
        bool allow_modeset : 1;
        bool legacy_cursor_update : 1;
        bool legacy_set_config : 1;
        struct __drm_planes_state *planes;
        struct __drm_crtcs_state *crtcs;
        int num_connector;
        struct __drm_connnectors_state *connectors;

        struct drm_modeset_acquire_ctx *acquire_ctx;

        /**
         * @commit_work:
         *
         * Work item which can be used by the driver or helpers to execute the
         * commit without blocking.
         */
        struct work_struct commit_work;
};


/**
 * struct drm_mode_set - new values for a CRTC config change
 * @fb: framebuffer to use for new config
 * @crtc: CRTC whose configuration we're about to change
 * @mode: mode timings to use
 * @x: position of this CRTC relative to @fb
 * @y: position of this CRTC relative to @fb
 * @connectors: array of connectors to drive with this CRTC if possible
 * @num_connectors: size of @connectors array
 *
 * Represents a single crtc the connectors that it drives with what mode
 * and from which framebuffer it scans out from.
 *
 * This is used to set modes.
 */
struct drm_mode_set {
        struct drm_framebuffer *fb;
        struct drm_crtc *crtc;
        struct drm_display_mode *mode;

        uint32_t x;
        uint32_t y;

        struct drm_connector **connectors;
        size_t num_connectors;
};

/**
 * struct drm_mode_config_funcs - basic driver provided mode setting functions
 *
 * Some global (i.e. not per-CRTC, connector, etc) mode setting functions that
 * involve drivers.
 */
struct drm_mode_config_funcs {
        /**
         * @fb_create:
         *
         * Create a new framebuffer object. The core does basic checks on the
         * requested metadata, but most of that is left to the driver. See
         * struct &drm_mode_fb_cmd2 for details.
         *
         * If the parameters are deemed valid and the backing storage objects in
         * the underlying memory manager all exist, then the driver allocates
         * a new &drm_framebuffer structure, subclassed to contain
         * driver-specific information (like the internal native buffer object
         * references). It also needs to fill out all relevant metadata, which
         * should be done by calling drm_helper_mode_fill_fb_struct().
         *
         * The initialization is finalized by calling drm_framebuffer_init(),
         * which registers the framebuffer and makes it accessible to other
         * threads.
         *
         * RETURNS:
         *
         * A new framebuffer with an initial reference count of 1 or a negative
         * error code encoded with ERR_PTR().
         */
        struct drm_framebuffer *(*fb_create)(struct drm_device *dev,
                                             struct drm_file *file_priv,
                                             const struct drm_mode_fb_cmd2 *mode_cmd);

        /**
         * @output_poll_changed:
         *
         * Callback used by helpers to inform the driver of output configuration
         * changes.
         *
         * Drivers implementing fbdev emulation with the helpers can call
         * drm_fb_helper_hotplug_changed from this hook to inform the fbdev
         * helper of output changes.
         *
         * FIXME:
         *
         * Except that there's no vtable for device-level helper callbacks
         * there's no reason this is a core function.
         */
        void (*output_poll_changed)(struct drm_device *dev);

        /**
         * @atomic_check:
         *
         * This is the only hook to validate an atomic modeset update. This
         * function must reject any modeset and state changes which the hardware
         * or driver doesn't support. This includes but is of course not limited
         * to:
         *
         *  - Checking that the modes, framebuffers, scaling and placement
         *    requirements and so on are within the limits of the hardware.
         *
         *  - Checking that any hidden shared resources are not oversubscribed.
         *    This can be shared PLLs, shared lanes, overall memory bandwidth,
         *    display fifo space (where shared between planes or maybe even
         *    CRTCs).
         *
         *  - Checking that virtualized resources exported to userspace are not
         *    oversubscribed. For various reasons it can make sense to expose
         *    more planes, crtcs or encoders than which are physically there. One
         *    example is dual-pipe operations (which generally should be hidden
         *    from userspace if when lockstepped in hardware, exposed otherwise),
         *    where a plane might need 1 hardware plane (if it's just on one
         *    pipe), 2 hardware planes (when it spans both pipes) or maybe even
         *    shared a hardware plane with a 2nd plane (if there's a compatible
         *    plane requested on the area handled by the other pipe).
         *
         *  - Check that any transitional state is possible and that if
         *    requested, the update can indeed be done in the vblank period
         *    without temporarily disabling some functions.
         *
         *  - Check any other constraints the driver or hardware might have.
         *
         *  - This callback also needs to correctly fill out the &drm_crtc_state
         *    in this update to make sure that drm_atomic_crtc_needs_modeset()
         *    reflects the nature of the possible update and returns true if and
         *    only if the update cannot be applied without tearing within one
         *    vblank on that CRTC. The core uses that information to reject
         *    updates which require a full modeset (i.e. blanking the screen, or
         *    at least pausing updates for a substantial amount of time) if
         *    userspace has disallowed that in its request.
         *
         *  - The driver also does not need to repeat basic input validation
         *    like done for the corresponding legacy entry points. The core does
         *    that before calling this hook.
         *
         * See the documentation of @atomic_commit for an exhaustive list of
         * error conditions which don't have to be checked at the
         * ->atomic_check() stage?
         *
         * See the documentation for struct &drm_atomic_state for how exactly
         * an atomic modeset update is described.
         *
         * Drivers using the atomic helpers can implement this hook using
         * drm_atomic_helper_check(), or one of the exported sub-functions of
         * it.
         *
         * RETURNS:
         *
         * 0 on success or one of the below negative error codes:
         *
         *  - -EINVAL, if any of the above constraints are violated.
         *
         *  - -EDEADLK, when returned from an attempt to acquire an additional
         *    &drm_modeset_lock through drm_modeset_lock().
         *
         *  - -ENOMEM, if allocating additional state sub-structures failed due
         *    to lack of memory.
         *
         *  - -EINTR, -EAGAIN or -ERESTARTSYS, if the IOCTL should be restarted.
         *    This can either be due to a pending signal, or because the driver
         *    needs to completely bail out to recover from an exceptional
         *    situation like a GPU hang. From a userspace point all errors are
         *    treated equally.
         */
        int (*atomic_check)(struct drm_device *dev,
                            struct drm_atomic_state *state);

        /**
         * @atomic_commit:
         *
         * This is the only hook to commit an atomic modeset update. The core
         * guarantees that @atomic_check has been called successfully before
         * calling this function, and that nothing has been changed in the
         * interim.
         *
         * See the documentation for struct &drm_atomic_state for how exactly
         * an atomic modeset update is described.
         *
         * Drivers using the atomic helpers can implement this hook using
         * drm_atomic_helper_commit(), or one of the exported sub-functions of
         * it.
         *
         * Nonblocking commits (as indicated with the nonblock parameter) must
         * do any preparatory work which might result in an unsuccessful commit
         * in the context of this callback. The only exceptions are hardware
         * errors resulting in -EIO. But even in that case the driver must
         * ensure that the display pipe is at least running, to avoid
         * compositors crashing when pageflips don't work. Anything else,
         * specifically committing the update to the hardware, should be done
         * without blocking the caller. For updates which do not require a
         * modeset this must be guaranteed.
         *
         * The driver must wait for any pending rendering to the new
         * framebuffers to complete before executing the flip. It should also
         * wait for any pending rendering from other drivers if the underlying
         * buffer is a shared dma-buf. Nonblocking commits must not wait for
         * rendering in the context of this callback.
         *
         * An application can request to be notified when the atomic commit has
         * completed. These events are per-CRTC and can be distinguished by the
         * CRTC index supplied in &drm_event to userspace.
         *
         * The drm core will supply a struct &drm_event in the event
         * member of each CRTC's &drm_crtc_state structure. This can be handled by the
         * drm_crtc_send_vblank_event() function, which the driver should call on
         * the provided event upon completion of the atomic commit. Note that if
         * the driver supports vblank signalling and timestamping the vblank
         * counters and timestamps must agree with the ones returned from page
         * flip events. With the current vblank helper infrastructure this can
         * be achieved by holding a vblank reference while the page flip is
         * pending, acquired through drm_crtc_vblank_get() and released with
         * drm_crtc_vblank_put(). Drivers are free to implement their own vblank
         * counter and timestamp tracking though, e.g. if they have accurate
         * timestamp registers in hardware.
         *
         * NOTE:
         *
         * Drivers are not allowed to shut down any display pipe successfully
         * enabled through an atomic commit on their own. Doing so can result in
         * compositors crashing if a page flip is suddenly rejected because the
         * pipe is off.
         *
         * RETURNS:
         *
         * 0 on success or one of the below negative error codes:
         *
         *  - -EBUSY, if a nonblocking updated is requested and there is
         *    an earlier updated pending. Drivers are allowed to support a queue
         *    of outstanding updates, but currently no driver supports that.
         *    Note that drivers must wait for preceding updates to complete if a
         *    synchronous update is requested, they are not allowed to fail the
         *    commit in that case.
         *
         *  - -ENOMEM, if the driver failed to allocate memory. Specifically
         *    this can happen when trying to pin framebuffers, which must only
         *    be done when committing the state.
         *
         *  - -ENOSPC, as a refinement of the more generic -ENOMEM to indicate
         *    that the driver has run out of vram, iommu space or similar GPU
         *    address space needed for framebuffer.
         *
         *  - -EIO, if the hardware completely died.
         *
         *  - -EINTR, -EAGAIN or -ERESTARTSYS, if the IOCTL should be restarted.
         *    This can either be due to a pending signal, or because the driver
         *    needs to completely bail out to recover from an exceptional
         *    situation like a GPU hang. From a userspace point of view all errors are
         *    treated equally.
         *
         * This list is exhaustive. Specifically this hook is not allowed to
         * return -EINVAL (any invalid requests should be caught in
         * @atomic_check) or -EDEADLK (this function must not acquire
         * additional modeset locks).
         */
        int (*atomic_commit)(struct drm_device *dev,
                             struct drm_atomic_state *state,
                             bool nonblock);

        /**
         * @atomic_state_alloc:
         *
         * This optional hook can be used by drivers that want to subclass struct
         * &drm_atomic_state to be able to track their own driver-private global
         * state easily. If this hook is implemented, drivers must also
         * implement @atomic_state_clear and @atomic_state_free.
         *
         * RETURNS:
         *
         * A new &drm_atomic_state on success or NULL on failure.
         */
        struct drm_atomic_state *(*atomic_state_alloc)(struct drm_device *dev);

        /**
         * @atomic_state_clear:
         *
         * This hook must clear any driver private state duplicated into the
         * passed-in &drm_atomic_state. This hook is called when the caller
         * encountered a &drm_modeset_lock deadlock and needs to drop all
         * already acquired locks as part of the deadlock avoidance dance
         * implemented in drm_modeset_lock_backoff().
         *
         * Any duplicated state must be invalidated since a concurrent atomic
         * update might change it, and the drm atomic interfaces always apply
         * updates as relative changes to the current state.
         *
         * Drivers that implement this must call drm_atomic_state_default_clear()
         * to clear common state.
         */
        void (*atomic_state_clear)(struct drm_atomic_state *state);

        /**
         * @atomic_state_free:
         *
         * This hook needs driver private resources and the &drm_atomic_state
         * itself. Note that the core first calls drm_atomic_state_clear() to
         * avoid code duplicate between the clear and free hooks.
         *
         * Drivers that implement this must call drm_atomic_state_default_free()
         * to release common resources.
         */
        void (*atomic_state_free)(struct drm_atomic_state *state);
};

/**
 * struct drm_mode_config - Mode configuration control structure
 * @mutex: mutex protecting KMS related lists and structures
 * @connection_mutex: ww mutex protecting connector state and routing
 * @acquire_ctx: global implicit acquire context used by atomic drivers for
 *      legacy IOCTLs
 * @fb_lock: mutex to protect fb state and lists
 * @num_fb: number of fbs available
 * @fb_list: list of framebuffers available
 * @num_encoder: number of encoders on this device
 * @encoder_list: list of encoder objects
 * @num_overlay_plane: number of overlay planes on this device
 * @num_total_plane: number of universal (i.e. with primary/curso) planes on this device
 * @plane_list: list of plane objects
 * @num_crtc: number of CRTCs on this device
 * @crtc_list: list of CRTC objects
 * @property_list: list of property objects
 * @min_width: minimum pixel width on this device
 * @min_height: minimum pixel height on this device
 * @max_width: maximum pixel width on this device
 * @max_height: maximum pixel height on this device
 * @funcs: core driver provided mode setting functions
 * @fb_base: base address of the framebuffer
 * @poll_enabled: track polling support for this device
 * @poll_running: track polling status for this device
 * @delayed_event: track delayed poll uevent deliver for this device
 * @output_poll_work: delayed work for polling in process context
 * @property_blob_list: list of all the blob property objects
 * @blob_lock: mutex for blob property allocation and management
 * @*_property: core property tracking
 * @preferred_depth: preferred RBG pixel depth, used by fb helpers
 * @prefer_shadow: hint to userspace to prefer shadow-fb rendering
 * @cursor_width: hint to userspace for max cursor width
 * @cursor_height: hint to userspace for max cursor height
 * @helper_private: mid-layer private data
 *
 * Core mode resource tracking structure.  All CRTC, encoders, and connectors
 * enumerated by the driver are added here, as are global properties.  Some
 * global restrictions are also here, e.g. dimension restrictions.
 */
struct drm_mode_config {
        struct mutex mutex; /* protects configuration (mode lists etc.) */
        struct drm_modeset_lock connection_mutex; /* protects connector->encoder and encoder->crtc links */
        struct drm_modeset_acquire_ctx *acquire_ctx; /* for legacy _lock_all() / _unlock_all() */

        /**
         * @idr_mutex:
         *
         * Mutex for KMS ID allocation and management. Protects both @crtc_idr
         * and @tile_idr.
         */
        struct mutex idr_mutex;

        /**
         * @crtc_idr:
         *
         * Main KMS ID tracking object. Use this idr for all IDs, fb, crtc,
         * connector, modes - just makes life easier to have only one.
         */
        struct idr crtc_idr;

        /**
         * @tile_idr:
         *
         * Use this idr for allocating new IDs for tiled sinks like use in some
         * high-res DP MST screens.
         */
        struct idr tile_idr;

        struct mutex fb_lock; /* proctects global and per-file fb lists */
        int num_fb;
        struct list_head fb_list;

        /**
         * @num_connector: Number of connectors on this device.
         */
        int num_connector;
        /**
         * @connector_ida: ID allocator for connector indices.
         */
        struct ida connector_ida;
        /**
         * @connector_list: List of connector objects.
         */
        struct list_head connector_list;
        int num_encoder;
        struct list_head encoder_list;

        /*
         * Track # of overlay planes separately from # of total planes.  By
         * default we only advertise overlay planes to userspace; if userspace
         * sets the "universal plane" capability bit, we'll go ahead and
         * expose all planes.
         */
        int num_overlay_plane;
        int num_total_plane;
        struct list_head plane_list;

        int num_crtc;
        struct list_head crtc_list;

        struct list_head property_list;

        int min_width, min_height;
        int max_width, max_height;
        const struct drm_mode_config_funcs *funcs;
        resource_size_t fb_base;

        /* output poll support */
        bool poll_enabled;
        bool poll_running;
        bool delayed_event;
        struct delayed_work output_poll_work;

        struct mutex blob_lock;

        /* pointers to standard properties */
        struct list_head property_blob_list;
        /**
         * @edid_property: Default connector property to hold the EDID of the
         * currently connected sink, if any.
         */
        struct drm_property *edid_property;
        /**
         * @dpms_property: Default connector property to control the
         * connector's DPMS state.
         */
        struct drm_property *dpms_property;
        /**
         * @path_property: Default connector property to hold the DP MST path
         * for the port.
         */
        struct drm_property *path_property;
        /**
         * @tile_property: Default connector property to store the tile
         * position of a tiled screen, for sinks which need to be driven with
         * multiple CRTCs.
         */
        struct drm_property *tile_property;
        /**
         * @plane_type_property: Default plane property to differentiate
         * CURSOR, PRIMARY and OVERLAY legacy uses of planes.
         */
        struct drm_property *plane_type_property;
        /**
         * @rotation_property: Optional property for planes or CRTCs to specifiy
         * rotation.
         */
        struct drm_property *rotation_property;
        /**
         * @prop_src_x: Default atomic plane property for the plane source
         * position in the connected &drm_framebuffer.
         */
        struct drm_property *prop_src_x;
        /**
         * @prop_src_y: Default atomic plane property for the plane source
         * position in the connected &drm_framebuffer.
         */
        struct drm_property *prop_src_y;
        /**
         * @prop_src_w: Default atomic plane property for the plane source
         * position in the connected &drm_framebuffer.
         */
        struct drm_property *prop_src_w;
        /**
         * @prop_src_h: Default atomic plane property for the plane source
         * position in the connected &drm_framebuffer.
         */
        struct drm_property *prop_src_h;
        /**
         * @prop_crtc_x: Default atomic plane property for the plane destination
         * position in the &drm_crtc is is being shown on.
         */
        struct drm_property *prop_crtc_x;
        /**
         * @prop_crtc_y: Default atomic plane property for the plane destination
         * position in the &drm_crtc is is being shown on.
         */
        struct drm_property *prop_crtc_y;
        /**
         * @prop_crtc_w: Default atomic plane property for the plane destination
         * position in the &drm_crtc is is being shown on.
         */
        struct drm_property *prop_crtc_w;
        /**
         * @prop_crtc_h: Default atomic plane property for the plane destination
         * position in the &drm_crtc is is being shown on.
         */
        struct drm_property *prop_crtc_h;
        /**
         * @prop_fb_id: Default atomic plane property to specify the
         * &drm_framebuffer.
         */
        struct drm_property *prop_fb_id;
        /**
         * @prop_crtc_id: Default atomic plane property to specify the
         * &drm_crtc.
         */
        struct drm_property *prop_crtc_id;
        /**
         * @prop_active: Default atomic CRTC property to control the active
         * state, which is the simplified implementation for DPMS in atomic
         * drivers.
         */
        struct drm_property *prop_active;
        /**
         * @prop_mode_id: Default atomic CRTC property to set the mode for a
         * CRTC. A 0 mode implies that the CRTC is entirely disabled - all
         * connectors must be of and active must be set to disabled, too.
         */
        struct drm_property *prop_mode_id;

        /**
         * @dvi_i_subconnector_property: Optional DVI-I property to
         * differentiate between analog or digital mode.
         */
        struct drm_property *dvi_i_subconnector_property;
        /**
         * @dvi_i_select_subconnector_property: Optional DVI-I property to
         * select between analog or digital mode.
         */
        struct drm_property *dvi_i_select_subconnector_property;

        /**
         * @tv_subconnector_property: Optional TV property to differentiate
         * between different TV connector types.
         */
        struct drm_property *tv_subconnector_property;
        /**
         * @tv_select_subconnector_property: Optional TV property to select
         * between different TV connector types.
         */
        struct drm_property *tv_select_subconnector_property;
        /**
         * @tv_mode_property: Optional TV property to select
         * the output TV mode.
         */
        struct drm_property *tv_mode_property;
        /**
         * @tv_left_margin_property: Optional TV property to set the left
         * margin.
         */
        struct drm_property *tv_left_margin_property;
        /**
         * @tv_right_margin_property: Optional TV property to set the right
         * margin.
         */
        struct drm_property *tv_right_margin_property;
        /**
         * @tv_top_margin_property: Optional TV property to set the right
         * margin.
         */
        struct drm_property *tv_top_margin_property;
        /**
         * @tv_bottom_margin_property: Optional TV property to set the right
         * margin.
         */
        struct drm_property *tv_bottom_margin_property;
        /**
         * @tv_brightness_property: Optional TV property to set the
         * brightness.
         */
        struct drm_property *tv_brightness_property;
        /**
         * @tv_contrast_property: Optional TV property to set the
         * contrast.
         */
        struct drm_property *tv_contrast_property;
        /**
         * @tv_flicker_reduction_property: Optional TV property to control the
         * flicker reduction mode.
         */
        struct drm_property *tv_flicker_reduction_property;
        /**
         * @tv_overscan_property: Optional TV property to control the overscan
         * setting.
         */
        struct drm_property *tv_overscan_property;
        /**
         * @tv_saturation_property: Optional TV property to set the
         * saturation.
         */
        struct drm_property *tv_saturation_property;
        /**
         * @tv_hue_property: Optional TV property to set the hue.
         */
        struct drm_property *tv_hue_property;

        /**
         * @scaling_mode_property: Optional connector property to control the
         * upscaling, mostly used for built-in panels.
         */
        struct drm_property *scaling_mode_property;
        /**
         * @aspect_ratio_property: Optional connector property to control the
         * HDMI infoframe aspect ratio setting.
         */
        struct drm_property *aspect_ratio_property;
        /**
         * @degamma_lut_property: Optional CRTC property to set the LUT used to
         * convert the framebuffer's colors to linear gamma.
         */
        struct drm_property *degamma_lut_property;
        /**
         * @degamma_lut_size_property: Optional CRTC property for the size of
         * the degamma LUT as supported by the driver (read-only).
         */
        struct drm_property *degamma_lut_size_property;
        /**
         * @ctm_property: Optional CRTC property to set the
         * matrix used to convert colors after the lookup in the
         * degamma LUT.
         */
        struct drm_property *ctm_property;
        /**
         * @gamma_lut_property: Optional CRTC property to set the LUT used to
         * convert the colors, after the CTM matrix, to the gamma space of the
         * connected screen.
         */
        struct drm_property *gamma_lut_property;
        /**
         * @gamma_lut_size_property: Optional CRTC property for the size of the
         * gamma LUT as supported by the driver (read-only).
         */
        struct drm_property *gamma_lut_size_property;

        /**
         * @suggested_x_property: Optional connector property with a hint for
         * the position of the output on the host's screen.
         */
        struct drm_property *suggested_x_property;
        /**
         * @suggested_y_property: Optional connector property with a hint for
         * the position of the output on the host's screen.
         */
        struct drm_property *suggested_y_property;

        /* dumb ioctl parameters */
        uint32_t preferred_depth, prefer_shadow;

        /**
         * @async_page_flip: Does this device support async flips on the primary
         * plane?
         */
        bool async_page_flip;

        /**
         * @allow_fb_modifiers:
         *
         * Whether the driver supports fb modifiers in the ADDFB2.1 ioctl call.
         */
        bool allow_fb_modifiers;

        /* cursor size */
        uint32_t cursor_width, cursor_height;

        struct drm_mode_config_helper_funcs *helper_private;
};

/**
 * drm_for_each_plane_mask - iterate over planes specified by bitmask
 * @plane: the loop cursor
 * @dev: the DRM device
 * @plane_mask: bitmask of plane indices
 *
 * Iterate over all planes specified by bitmask.
 */
#define drm_for_each_plane_mask(plane, dev, plane_mask) \
        list_for_each_entry((plane), &(dev)->mode_config.plane_list, head) \
                for_each_if ((plane_mask) & (1 << drm_plane_index(plane)))

/**
 * drm_for_each_encoder_mask - iterate over encoders specified by bitmask
 * @encoder: the loop cursor
 * @dev: the DRM device
 * @encoder_mask: bitmask of encoder indices
 *
 * Iterate over all encoders specified by bitmask.
 */
#define drm_for_each_encoder_mask(encoder, dev, encoder_mask) \
        list_for_each_entry((encoder), &(dev)->mode_config.encoder_list, head) \
                for_each_if ((encoder_mask) & (1 << drm_encoder_index(encoder)))

#define obj_to_crtc(x) container_of(x, struct drm_crtc, base)
#define obj_to_mode(x) container_of(x, struct drm_display_mode, base)
#define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)
#define obj_to_property(x) container_of(x, struct drm_property, base)
#define obj_to_blob(x) container_of(x, struct drm_property_blob, base)
#define obj_to_plane(x) container_of(x, struct drm_plane, base)

struct drm_prop_enum_list {
        int type;
        char *name;
};

extern __printf(6, 7)
int drm_crtc_init_with_planes(struct drm_device *dev,
                              struct drm_crtc *crtc,
                              struct drm_plane *primary,
                              struct drm_plane *cursor,
                              const struct drm_crtc_funcs *funcs,
                              const char *name, ...);
extern void drm_crtc_cleanup(struct drm_crtc *crtc);

/**
 * drm_crtc_index - find the index of a registered CRTC
 * @crtc: CRTC to find index for
 *
 * Given a registered CRTC, return the index of that CRTC within a DRM
 * device's list of CRTCs.
 */
static inline unsigned int drm_crtc_index(struct drm_crtc *crtc)
{
        return crtc->index;
}

/**
 * drm_crtc_mask - find the mask of a registered CRTC
 * @crtc: CRTC to find mask for
 *
 * Given a registered CRTC, return the mask bit of that CRTC for an
 * encoder's possible_crtcs field.
 */
static inline uint32_t drm_crtc_mask(struct drm_crtc *crtc)
{
        return 1 << drm_crtc_index(crtc);
}

extern __printf(8, 9)
int drm_universal_plane_init(struct drm_device *dev,
                             struct drm_plane *plane,
                             unsigned long possible_crtcs,
                             const struct drm_plane_funcs *funcs,
                             const uint32_t *formats,
                             unsigned int format_count,
                             enum drm_plane_type type,
                             const char *name, ...);
extern int drm_plane_init(struct drm_device *dev,
                          struct drm_plane *plane,
                          unsigned long possible_crtcs,
                          const struct drm_plane_funcs *funcs,
                          const uint32_t *formats, unsigned int format_count,
                          bool is_primary);
extern void drm_plane_cleanup(struct drm_plane *plane);

/**
 * drm_plane_index - find the index of a registered plane
 * @plane: plane to find index for
 *
 * Given a registered plane, return the index of that plane within a DRM
 * device's list of planes.
 */
static inline unsigned int drm_plane_index(struct drm_plane *plane)
{
        return plane->index;
}
extern struct drm_plane * drm_plane_from_index(struct drm_device *dev, int idx);
extern void drm_plane_force_disable(struct drm_plane *plane);
extern void drm_crtc_get_hv_timing(const struct drm_display_mode *mode,
                                   int *hdisplay, int *vdisplay);
extern int drm_crtc_force_disable(struct drm_crtc *crtc);
extern int drm_crtc_force_disable_all(struct drm_device *dev);

extern void drm_mode_config_init(struct drm_device *dev);
extern void drm_mode_config_reset(struct drm_device *dev);
extern void drm_mode_config_cleanup(struct drm_device *dev);

static inline bool drm_property_type_is(struct drm_property *property,
                uint32_t type)
{
        /* instanceof for props.. handles extended type vs original types: */
        if (property->flags & DRM_MODE_PROP_EXTENDED_TYPE)
                return (property->flags & DRM_MODE_PROP_EXTENDED_TYPE) == type;
        return property->flags & type;
}

extern struct drm_property *drm_property_create(struct drm_device *dev, int flags,
                                                const char *name, int num_values);
extern struct drm_property *drm_property_create_enum(struct drm_device *dev, int flags,
                                         const char *name,
                                         const struct drm_prop_enum_list *props,
                                         int num_values);
struct drm_property *drm_property_create_bitmask(struct drm_device *dev,
                                         int flags, const char *name,
                                         const struct drm_prop_enum_list *props,
                                         int num_props,
                                         uint64_t supported_bits);
struct drm_property *drm_property_create_range(struct drm_device *dev, int flags,
                                         const char *name,
                                         uint64_t min, uint64_t max);
struct drm_property *drm_property_create_signed_range(struct drm_device *dev,
                                         int flags, const char *name,
                                         int64_t min, int64_t max);
struct drm_property *drm_property_create_object(struct drm_device *dev,
                                         int flags, const char *name, uint32_t type);
struct drm_property *drm_property_create_bool(struct drm_device *dev, int flags,
                                         const char *name);
struct drm_property_blob *drm_property_create_blob(struct drm_device *dev,
                                                   size_t length,
                                                   const void *data);
struct drm_property_blob *drm_property_lookup_blob(struct drm_device *dev,
                                                   uint32_t id);
int drm_property_replace_global_blob(struct drm_device *dev,
                                     struct drm_property_blob **replace,
                                     size_t length,
                                     const void *data,
                                     struct drm_mode_object *obj_holds_id,
                                     struct drm_property *prop_holds_id);
struct drm_property_blob *drm_property_reference_blob(struct drm_property_blob *blob);
void drm_property_unreference_blob(struct drm_property_blob *blob);
extern void drm_property_destroy(struct drm_device *dev, struct drm_property *property);
extern int drm_property_add_enum(struct drm_property *property, int index,
                                 uint64_t value, const char *name);
extern int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
                                         int gamma_size);

extern int drm_mode_set_config_internal(struct drm_mode_set *set);

extern struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
                                                         char topology[8]);
extern struct drm_tile_group *drm_mode_get_tile_group(struct drm_device *dev,
                                               char topology[8]);
extern void drm_mode_put_tile_group(struct drm_device *dev,
                                   struct drm_tile_group *tg);

extern int drm_mode_plane_set_obj_prop(struct drm_plane *plane,
                                       struct drm_property *property,
                                       uint64_t value);

extern struct drm_property *drm_mode_create_rotation_property(struct drm_device *dev,
                                                              unsigned int supported_rotations);
extern unsigned int drm_rotation_simplify(unsigned int rotation,
                                          unsigned int supported_rotations);
extern void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
                                       uint degamma_lut_size,
                                       bool has_ctm,
                                       uint gamma_lut_size);

int drm_plane_create_zpos_property(struct drm_plane *plane,
                                   unsigned int zpos,
                                   unsigned int min, unsigned int max);

int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,
                                             unsigned int zpos);

/* Helpers */
static inline struct drm_plane *drm_plane_find(struct drm_device *dev,
                uint32_t id)
{
        struct drm_mode_object *mo;
        mo = drm_mode_object_find(dev, id, DRM_MODE_OBJECT_PLANE);
        return mo ? obj_to_plane(mo) : NULL;
}

static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev,
        uint32_t id)
{
        struct drm_mode_object *mo;
        mo = drm_mode_object_find(dev, id, DRM_MODE_OBJECT_CRTC);
        return mo ? obj_to_crtc(mo) : NULL;
}

static inline struct drm_property *drm_property_find(struct drm_device *dev,
                uint32_t id)
{
        struct drm_mode_object *mo;
        mo = drm_mode_object_find(dev, id, DRM_MODE_OBJECT_PROPERTY);
        return mo ? obj_to_property(mo) : NULL;
}

/*
 * Extract a degamma/gamma LUT value provided by user and round it to the
 * precision supported by the hardware.
 */
static inline uint32_t drm_color_lut_extract(uint32_t user_input,
                                             uint32_t bit_precision)
{
        uint32_t val = user_input;
        uint32_t max = 0xffff >> (16 - bit_precision);

        /* Round only if we're not using full precision. */
        if (bit_precision < 16) {
                val += 1UL << (16 - bit_precision - 1);
                val >>= 16 - bit_precision;
        }

        return clamp_val(val, 0, max);
}

/* Plane list iterator for legacy (overlay only) planes. */
#define drm_for_each_legacy_plane(plane, dev) \
        list_for_each_entry(plane, &(dev)->mode_config.plane_list, head) \
                for_each_if (plane->type == DRM_PLANE_TYPE_OVERLAY)

#define drm_for_each_plane(plane, dev) \
        list_for_each_entry(plane, &(dev)->mode_config.plane_list, head)

#define drm_for_each_crtc(crtc, dev) \
        list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head)

static inline void
assert_drm_connector_list_read_locked(struct drm_mode_config *mode_config)
{
        /*
         * The connector hotadd/remove code currently grabs both locks when
         * updating lists. Hence readers need only hold either of them to be
         * safe and the check amounts to
         *
         * WARN_ON(not_holding(A) && not_holding(B)).
         */
        WARN_ON(!mutex_is_locked(&mode_config->mutex) &&
                !drm_modeset_is_locked(&mode_config->connection_mutex));
}

#define drm_for_each_connector(connector, dev) \
        for (assert_drm_connector_list_read_locked(&(dev)->mode_config),        \
             connector = list_first_entry(&(dev)->mode_config.connector_list,   \
                                          struct drm_connector, head);          \
             &connector->head != (&(dev)->mode_config.connector_list);          \
             connector = list_next_entry(connector, head))

#define drm_for_each_encoder(encoder, dev) \
        list_for_each_entry(encoder, &(dev)->mode_config.encoder_list, head)

#define drm_for_each_fb(fb, dev) \
        for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)),            \
             fb = list_first_entry(&(dev)->mode_config.fb_list, \
                                          struct drm_framebuffer, head);        \
             &fb->head != (&(dev)->mode_config.fb_list);                        \
             fb = list_next_entry(fb, head))

/* drm_edid.c */
bool drm_probe_ddc(struct i2c_adapter *adapter);
struct edid *drm_get_edid(struct drm_connector *connector,
                          struct i2c_adapter *adapter);
struct edid *drm_get_edid_switcheroo(struct drm_connector *connector,
                                     struct i2c_adapter *adapter);
struct edid *drm_edid_duplicate(const struct edid *edid);
int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid);

u8 drm_match_cea_mode(const struct drm_display_mode *to_match);
enum hdmi_picture_aspect drm_get_cea_aspect_ratio(const u8 video_code);
bool drm_detect_hdmi_monitor(struct edid *edid);
bool drm_detect_monitor_audio(struct edid *edid);
bool drm_rgb_quant_range_selectable(struct edid *edid);
int drm_add_modes_noedid(struct drm_connector *connector,
                         int hdisplay, int vdisplay);
void drm_set_preferred_mode(struct drm_connector *connector,
                            int hpref, int vpref);

int drm_edid_header_is_valid(const u8 *raw_edid);
bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid,
                          bool *edid_corrupt);
bool drm_edid_is_valid(struct edid *edid);
void drm_edid_get_monitor_name(struct edid *edid, char *name,
                               int buflen);
struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
                                           int hsize, int vsize, int fresh,
                                           bool rb);

/* drm_bridge.c */
extern int drm_bridge_add(struct drm_bridge *bridge);
extern void drm_bridge_remove(struct drm_bridge *bridge);
extern struct drm_bridge *of_drm_find_bridge(struct device_node *np);
extern int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge);
extern void drm_bridge_detach(struct drm_bridge *bridge);

bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
                        const struct drm_display_mode *mode,
                        struct drm_display_mode *adjusted_mode);
void drm_bridge_disable(struct drm_bridge *bridge);
void drm_bridge_post_disable(struct drm_bridge *bridge);
void drm_bridge_mode_set(struct drm_bridge *bridge,
                        struct drm_display_mode *mode,
                        struct drm_display_mode *adjusted_mode);
void drm_bridge_pre_enable(struct drm_bridge *bridge);
void drm_bridge_enable(struct drm_bridge *bridge);

#endif /* __DRM_CRTC_H__ */