[PATCH 2/2] drm: Parse color format information in CEA blocks

[Lars-Peter Clausen]

The CEA extension block has a field which contains the YCbCr modes supported by
the device. Use the information from this field to initialize the
drm_display_info color_formats. Also the existence of a CEA extension block
should allow us to assume that the device supports RGB.

Signed-off-by: Lars-Peter Clausen <lars at metafoo.de>
---
 drivers/gpu/drm/drm_edid.c |   31 +++++++++++++++++++++----------
 1 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index a6bb2f5..390aeca 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1313,6 +1313,8 @@ 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.
@@ -1667,13 +1669,29 @@ 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;
@@ -1699,18 +1717,11 @@ 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];
 }
 
 /**
-- 
1.7.9