Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.15
Cc: Shawn C Lee <shawn.c.lee@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
commit e28ad544f462 was merged in v5.3, but it has Cc: stable for v4.15.
This is also fixed in my CEA data block iteration series [1], but we'll
want the simple fix for stable first.
Hum, CTA is formerly CEA, I and the code seem to use both, should we use
only one or the other?
[1] https://patchwork.freedesktop.org/series/101659/
---
drivers/gpu/drm/drm_edid.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 561f53831e29..ccf7031a6797 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5187,10 +5187,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* 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_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
--
2.30.2
