Merge tag 'platform-drivers-x86-v4.1-1' of git://git.infradead.org/users/dvhart/linux...

[sfrench/cifs-2.6.git] / drivers / platform / x86 / apple-gmux.c

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 66d6d22c239c2b2231ca6837bc36d4cd89a9edb7..6808715003f6e7e40d6b5bb9d60c6533efff2c26 100644 (file)
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -22,6 +22,7 @@
 #include <linux/delay.h>
 #include <linux/pci.h>
 #include <linux/vga_switcheroo.h>
+#include <linux/vgaarb.h>
 #include <acpi/video.h>
 #include <asm/io.h>
 
@@ -31,6 +32,7 @@ struct apple_gmux_data {
        bool indexed;
        struct mutex index_lock;
 
+       struct pci_dev *pdev;
        struct backlight_device *bdev;
 
        /* switcheroo data */
@@ -415,6 +417,23 @@ static int gmux_resume(struct device *dev)
        return 0;
 }
 
+static struct pci_dev *gmux_get_io_pdev(void)
+{
+       struct pci_dev *pdev = NULL;
+
+       while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
+               u16 cmd;
+
+               pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+               if (!(cmd & PCI_COMMAND_IO))
+                       continue;
+
+               return pdev;
+       }
+
+       return NULL;
+}
+
 static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 {
        struct apple_gmux_data *gmux_data;
@@ -425,6 +444,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
        int ret = -ENXIO;
        acpi_status status;
        unsigned long long gpe;
+       struct pci_dev *pdev = NULL;
 
        if (apple_gmux_data)
                return -EBUSY;
@@ -475,7 +495,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
                        ver_minor = (version >> 16) & 0xff;
                        ver_release = (version >> 8) & 0xff;
                } else {
-                       pr_info("gmux device not present\n");
+                       pr_info("gmux device not present or IO disabled\n");
                        ret = -ENODEV;
                        goto err_release;
                }
@@ -483,6 +503,23 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
        pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
                ver_release, (gmux_data->indexed ? "indexed" : "classic"));
 
+       /*
+        * Apple systems with gmux are EFI based and normally don't use
+        * VGA. In addition changing IO+MEM ownership between IGP and dGPU
+        * disables IO/MEM used for backlight control on some systems.
+        * Lock IO+MEM to GPU with active IO to prevent switch.
+        */
+       pdev = gmux_get_io_pdev();
+       if (pdev && vga_tryget(pdev,
+                              VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
+               pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
+                       pci_name(pdev));
+               ret = -EBUSY;
+               goto err_release;
+       } else if (pdev)
+               pr_info("locked IO for PCI:%s\n", pci_name(pdev));
+       gmux_data->pdev = pdev;
+
        memset(&props, 0, sizeof(props));
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
@@ -574,6 +611,10 @@ err_enable_gpe:
 err_notify:
        backlight_device_unregister(bdev);
 err_release:
+       if (gmux_data->pdev)
+               vga_put(gmux_data->pdev,
+                       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+       pci_dev_put(pdev);
        release_region(gmux_data->iostart, gmux_data->iolen);
 err_free:
        kfree(gmux_data);
@@ -593,6 +634,11 @@ static void gmux_remove(struct pnp_dev *pnp)
                                           &gmux_notify_handler);
        }
 
+       if (gmux_data->pdev) {
+               vga_put(gmux_data->pdev,
+                       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+               pci_dev_put(gmux_data->pdev);
+       }
        backlight_device_unregister(gmux_data->bdev);
 
        release_region(gmux_data->iostart, gmux_data->iolen);