drm/nouveau: support fetching LVDS EDID from ACPI

Based on a patch from Matthew Garrett.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Matthew Garrett <mjg@redhat.com>

5 files changed, 59 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 381d3851f5c3..c17a055ee3e5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -3,6 +3,7 @@
 #include <linux/slab.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/acpi_bus.h>
+#include <acpi/video.h>
 
 #include "drmP.h"
 #include "drm.h"
@@ -11,6 +12,7 @@
 #include "nouveau_drv.h"
 #include "nouveau_drm.h"
 #include "nv50_display.h"
+#include "nouveau_connector.h"
 
 #include <linux/vga_switcheroo.h>
 
@@ -259,3 +261,37 @@ int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len)
 {
         return nouveau_rom_call(nouveau_dsm_priv.rom_handle, bios, offset, len);
 }
+
+int
+nouveau_acpi_edid(struct drm_device *dev, struct drm_connector *connector)
+{
+        struct nouveau_connector *nv_connector = nouveau_connector(connector);
+        struct acpi_device *acpidev;
+        acpi_handle handle;
+        int type, ret;
+        void *edid;
+
+        switch (connector->connector_type) {
+        case DRM_MODE_CONNECTOR_LVDS:
+        case DRM_MODE_CONNECTOR_eDP:
+                type = ACPI_VIDEO_DISPLAY_LCD;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        handle = DEVICE_ACPI_HANDLE(&dev->pdev->dev);
+        if (!handle)
+                return -ENODEV;
+
+        ret = acpi_bus_get_device(handle, &acpidev);
+        if (ret)
+                return -ENODEV;
+
+        ret = acpi_video_get_edid(acpidev, type, -1, &edid);
+        if (ret < 0)
+                return ret;
+
+        nv_connector->edid = edid;
+        return 0;
+}
diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c
index 2297bbc88c6f..256c6ed7d9e0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.c
@@ -5622,7 +5622,9 @@ parse_dcb20_entry(struct drm_device *dev, struct dcb_table *dcb,
                         if (conf & 0x4 || conf & 0x8)
                                 entry->lvdsconf.use_power_scripts = true;
                 } else {
-                        mask = ~0x5;
+                        mask = ~0x7;
+                        if (conf & 0x2)
+                                entry->lvdsconf.use_acpi_for_edid = true;
                         if (conf & 0x4)
                                 entry->lvdsconf.use_power_scripts = true;
                 }
diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.h b/drivers/gpu/drm/nouveau/nouveau_bios.h
index bd33a54f7deb..cc52aec33691 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.h
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.h
@@ -118,6 +118,7 @@ struct dcb_entry {
                 struct {
                         struct sor_conf sor;
                         bool use_straps_for_mode;
+                        bool use_acpi_for_edid;
                         bool use_power_scripts;
                 } lvdsconf;
                 struct {
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index c2fb15311b96..50704287a8c2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -327,12 +327,29 @@ nouveau_connector_detect_lvds(struct drm_connector *connector)
         if (!nv_encoder)
                 return connector_status_disconnected;
 
+        /* Try retrieving EDID via DDC */
         if (!dev_priv->vbios.fp_no_ddc) {
                 status = nouveau_connector_detect(connector);
                 if (status == connector_status_connected)
                         goto out;
         }
 
+        /* On some laptops (Sony, i'm looking at you) there appears to
+         * be no direct way of accessing the panel's EDID.  The only
+         * option available to us appears to be to ask ACPI for help..
+         *
+         * It's important this check's before trying straps, one of the
+         * said manufacturer's laptops are configured in such a way
+         * the nouveau decides an entry in the VBIOS FP mode table is
+         * valid - it's not (rh#613284)
+         */
+        if (nv_encoder->dcb->lvdsconf.use_acpi_for_edid) {
+                if (!nouveau_acpi_edid(dev, connector)) {
+                        status = connector_status_connected;
+                        goto out;
+                }
+        }
+
         /* If no EDID found above, and the VBIOS indicates a hardcoded
          * modeline is avalilable for the panel, set it as the panel's
          * native mode and exit.
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 16856e0354f8..20ca5b82ad6f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -827,11 +827,13 @@ void nouveau_register_dsm_handler(void);
 void nouveau_unregister_dsm_handler(void);
 int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len);
 bool nouveau_acpi_rom_supported(struct pci_dev *pdev);
+int nouveau_acpi_edid(struct drm_device *, struct drm_connector *);
 #else
 static inline void nouveau_register_dsm_handler(void) {}
 static inline void nouveau_unregister_dsm_handler(void) {}
 static inline bool nouveau_acpi_rom_supported(struct pci_dev *pdev) { return false; }
 static inline int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len) { return -EINVAL; }
+static inline int nouveau_acpi_edid(struct drm_device *, struct drm_connector *) { return -EINVAL; }
 #endif
 
 /* nouveau_backlight.c */