drm: Parse color format information in CEA blocks

The CEA extension block has a field which describes which YCbCr modes are
supported by the device, use it to fill the drm_display_info color_formats
fields. Also the existence of a CEA extension block is used as indication
that the device supports RGB.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 21 insertions, 10 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 8a4580c2a1d0..e07491088400 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1312,6 +1312,8 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
 #define VENDOR_BLOCK    0x03
 #define SPEAKER_BLOCK   0x04
 #define EDID_BASIC_AUDIO        (1 << 6)
+#define EDID_CEA_YCRCB444       (1 << 5)
+#define EDID_CEA_YCRCB422       (1 << 4)
 
 /**
  * Search EDID for CEA extension block.
@@ -1666,13 +1668,29 @@ static void drm_add_display_info(struct edid *edid,
         info->bpc = 0;
         info->color_formats = 0;
 
-        /* Only defined for 1.4 with digital displays */
-        if (edid->revision < 4)
+        if (edid->revision < 3)
                 return;
 
         if (!(edid->input & DRM_EDID_INPUT_DIGITAL))
                 return;
 
+        /* Get data from CEA blocks if present */
+        edid_ext = drm_find_cea_extension(edid);
+        if (edid_ext) {
+                info->cea_rev = edid_ext[1];
+
+                /* The existence of a CEA block should imply RGB support */
+                info->color_formats = DRM_COLOR_FORMAT_RGB444;
+                if (edid_ext[3] & EDID_CEA_YCRCB444)
+                        info->color_formats |= DRM_COLOR_FORMAT_YCRCB444;
+                if (edid_ext[3] & EDID_CEA_YCRCB422)
+                        info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
+        }
+
+        /* Only defined for 1.4 with digital displays */
+        if (edid->revision < 4)
+                return;
+
         switch (edid->input & DRM_EDID_DIGITAL_DEPTH_MASK) {
         case DRM_EDID_DIGITAL_DEPTH_6:
                 info->bpc = 6;
@@ -1698,18 +1716,11 @@ static void drm_add_display_info(struct edid *edid,
                 break;
         }
 
-        info->color_formats = DRM_COLOR_FORMAT_RGB444;
+        info->color_formats |= DRM_COLOR_FORMAT_RGB444;
         if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB444)
                 info->color_formats |= DRM_COLOR_FORMAT_YCRCB444;
         if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB422)
                 info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
-
-        /* Get data from CEA blocks if present */
-        edid_ext = drm_find_cea_extension(edid);
-        if (!edid_ext)
-                return;
-
-        info->cea_rev = edid_ext[1];
 }
 
 /**