2 * Copyright (c) 2016 Intel Corporation
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5 * documentation for any purpose is hereby granted without fee, provided that
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24 #include <drm/drm_crtc.h>
25 #include <drm/drm_color_mgmt.h>
27 #include "drm_crtc_internal.h"
32 * Color management or color space adjustments is supported through a set of 5
33 * properties on the &drm_crtc object. They are set up by calling
34 * drm_crtc_enable_color_mgmt().
37 * Blob property to set the degamma lookup table (LUT) mapping pixel data
38 * from the framebuffer before it is given to the transformation matrix.
39 * The data is interpreted as an array of &struct drm_color_lut elements.
40 * Hardware might choose not to use the full precision of the LUT elements
41 * nor use all the elements of the LUT (for example the hardware might
42 * choose to interpolate between LUT[0] and LUT[4]).
44 * Setting this to NULL (blob property value set to 0) means a
45 * linear/pass-thru gamma table should be used. This is generally the
46 * driver boot-up state too.
49 * Unsinged range property to give the size of the lookup table to be set
50 * on the DEGAMMA_LUT property (the size depends on the underlying
51 * hardware). If drivers support multiple LUT sizes then they should
52 * publish the largest size, and sub-sample smaller sized LUTs (e.g. for
53 * split-gamma modes) appropriately.
56 * Blob property to set the current transformation matrix (CTM) apply to
57 * pixel data after the lookup through the degamma LUT and before the
58 * lookup through the gamma LUT. The data is interpreted as a struct
61 * Setting this to NULL (blob property value set to 0) means a
62 * unit/pass-thru matrix should be used. This is generally the driver
66 * Blob property to set the gamma lookup table (LUT) mapping pixel data
67 * after the transformation matrix to data sent to the connector. The
68 * data is interpreted as an array of &struct drm_color_lut elements.
69 * Hardware might choose not to use the full precision of the LUT elements
70 * nor use all the elements of the LUT (for example the hardware might
71 * choose to interpolate between LUT[0] and LUT[4]).
73 * Setting this to NULL (blob property value set to 0) means a
74 * linear/pass-thru gamma table should be used. This is generally the
75 * driver boot-up state too.
78 * Unsigned range property to give the size of the lookup table to be set
79 * on the GAMMA_LUT property (the size depends on the underlying hardware).
80 * If drivers support multiple LUT sizes then they should publish the
81 * largest size, and sub-sample smaller sized LUTs (e.g. for split-gamma
82 * modes) appropriately.
84 * There is also support for a legacy gamma table, which is set up by calling
85 * drm_mode_crtc_set_gamma_size(). Drivers which support both should use
86 * drm_atomic_helper_legacy_gamma_set() to alias the legacy gamma ramp with the
87 * "GAMMA_LUT" property above.
91 * drm_color_lut_extract - clamp and round LUT entries
92 * @user_input: input value
93 * @bit_precision: number of bits the hw LUT supports
95 * Extract a degamma/gamma LUT value provided by user (in the form of
96 * &drm_color_lut entries) and round it to the precision supported by the
99 uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision)
101 uint32_t val = user_input;
102 uint32_t max = 0xffff >> (16 - bit_precision);
104 /* Round only if we're not using full precision. */
105 if (bit_precision < 16) {
106 val += 1UL << (16 - bit_precision - 1);
107 val >>= 16 - bit_precision;
110 return clamp_val(val, 0, max);
112 EXPORT_SYMBOL(drm_color_lut_extract);
115 * drm_crtc_enable_color_mgmt - enable color management properties
117 * @degamma_lut_size: the size of the degamma lut (before CSC)
118 * @has_ctm: whether to attach ctm_property for CSC matrix
119 * @gamma_lut_size: the size of the gamma lut (after CSC)
121 * This function lets the driver enable the color correction
122 * properties on a CRTC. This includes 3 degamma, csc and gamma
123 * properties that userspace can set and 2 size properties to inform
124 * the userspace of the lut sizes. Each of the properties are
125 * optional. The gamma and degamma properties are only attached if
126 * their size is not 0 and ctm_property is only attached if has_ctm is
129 void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
130 uint degamma_lut_size,
134 struct drm_device *dev = crtc->dev;
135 struct drm_mode_config *config = &dev->mode_config;
137 if (degamma_lut_size) {
138 drm_object_attach_property(&crtc->base,
139 config->degamma_lut_property, 0);
140 drm_object_attach_property(&crtc->base,
141 config->degamma_lut_size_property,
146 drm_object_attach_property(&crtc->base,
147 config->ctm_property, 0);
149 if (gamma_lut_size) {
150 drm_object_attach_property(&crtc->base,
151 config->gamma_lut_property, 0);
152 drm_object_attach_property(&crtc->base,
153 config->gamma_lut_size_property,
157 EXPORT_SYMBOL(drm_crtc_enable_color_mgmt);
160 * drm_mode_crtc_set_gamma_size - set the gamma table size
161 * @crtc: CRTC to set the gamma table size for
162 * @gamma_size: size of the gamma table
164 * Drivers which support gamma tables should set this to the supported gamma
165 * table size when initializing the CRTC. Currently the drm core only supports a
166 * fixed gamma table size.
169 * Zero on success, negative errno on failure.
171 int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
174 uint16_t *r_base, *g_base, *b_base;
177 crtc->gamma_size = gamma_size;
179 crtc->gamma_store = kcalloc(gamma_size, sizeof(uint16_t) * 3,
181 if (!crtc->gamma_store) {
182 crtc->gamma_size = 0;
186 r_base = crtc->gamma_store;
187 g_base = r_base + gamma_size;
188 b_base = g_base + gamma_size;
189 for (i = 0; i < gamma_size; i++) {
198 EXPORT_SYMBOL(drm_mode_crtc_set_gamma_size);
201 * drm_mode_gamma_set_ioctl - set the gamma table
204 * @file_priv: DRM file info
206 * Set the gamma table of a CRTC to the one passed in by the user. Userspace can
207 * inquire the required gamma table size through drm_mode_gamma_get_ioctl.
209 * Called by the user via ioctl.
212 * Zero on success, negative errno on failure.
214 int drm_mode_gamma_set_ioctl(struct drm_device *dev,
215 void *data, struct drm_file *file_priv)
217 struct drm_mode_crtc_lut *crtc_lut = data;
218 struct drm_crtc *crtc;
219 void *r_base, *g_base, *b_base;
221 struct drm_modeset_acquire_ctx ctx;
224 if (!drm_core_check_feature(dev, DRIVER_MODESET))
227 crtc = drm_crtc_find(dev, crtc_lut->crtc_id);
231 if (crtc->funcs->gamma_set == NULL)
234 /* memcpy into gamma store */
235 if (crtc_lut->gamma_size != crtc->gamma_size)
238 drm_modeset_acquire_init(&ctx, 0);
240 ret = drm_modeset_lock_all_ctx(dev, &ctx);
244 size = crtc_lut->gamma_size * (sizeof(uint16_t));
245 r_base = crtc->gamma_store;
246 if (copy_from_user(r_base, (void __user *)(unsigned long)crtc_lut->red, size)) {
251 g_base = r_base + size;
252 if (copy_from_user(g_base, (void __user *)(unsigned long)crtc_lut->green, size)) {
257 b_base = g_base + size;
258 if (copy_from_user(b_base, (void __user *)(unsigned long)crtc_lut->blue, size)) {
263 ret = crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
264 crtc->gamma_size, &ctx);
267 if (ret == -EDEADLK) {
268 drm_modeset_backoff(&ctx);
271 drm_modeset_drop_locks(&ctx);
272 drm_modeset_acquire_fini(&ctx);
279 * drm_mode_gamma_get_ioctl - get the gamma table
282 * @file_priv: DRM file info
284 * Copy the current gamma table into the storage provided. This also provides
285 * the gamma table size the driver expects, which can be used to size the
288 * Called by the user via ioctl.
291 * Zero on success, negative errno on failure.
293 int drm_mode_gamma_get_ioctl(struct drm_device *dev,
294 void *data, struct drm_file *file_priv)
296 struct drm_mode_crtc_lut *crtc_lut = data;
297 struct drm_crtc *crtc;
298 void *r_base, *g_base, *b_base;
302 if (!drm_core_check_feature(dev, DRIVER_MODESET))
305 crtc = drm_crtc_find(dev, crtc_lut->crtc_id);
309 /* memcpy into gamma store */
310 if (crtc_lut->gamma_size != crtc->gamma_size)
313 drm_modeset_lock(&crtc->mutex, NULL);
314 size = crtc_lut->gamma_size * (sizeof(uint16_t));
315 r_base = crtc->gamma_store;
316 if (copy_to_user((void __user *)(unsigned long)crtc_lut->red, r_base, size)) {
321 g_base = r_base + size;
322 if (copy_to_user((void __user *)(unsigned long)crtc_lut->green, g_base, size)) {
327 b_base = g_base + size;
328 if (copy_to_user((void __user *)(unsigned long)crtc_lut->blue, b_base, size)) {
333 drm_modeset_unlock(&crtc->mutex);