[PATCH v2 01/14] drm/edid: Don't clear YUV422 if using deep color

[Maxime Ripard]

The current code, when parsing the EDID Deep Color depths, that the
YUV422 cannot be used, referring to the HDMI 1.3 Specification.

This specification, in its section 6.2.4, indeed states:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is not permitted for any Deep Color mode.

This indeed can be interpreted like the code does, but the HDMI 1.4
specification further clarifies that statement in its section 6.2.4:

  For each supported Deep Color mode, RGB 4:4:4 shall be supported and
  optionally YCBCR 4:4:4 may be supported.

  YCBCR 4:2:2 is also 36-bit mode but does not require the further use
  of the Deep Color modes described in section 6.5.2 and 6.5.3.

This means that, even though YUV422 can be used with 12 bit per color,
it shouldn't be treated as a deep color mode.

This deviates from the interpretation of the code and comment, so let's
fix those.

Fixes: d0c94692e0a3 ("drm/edid: Parse and handle HDMI deep color modes.")
Signed-off-by: Maxime Ripard <maxime at cerno.tech>
---
 drivers/gpu/drm/drm_edid.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 12893e7be89b..e57d1b8cdaaa 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5106,10 +5106,9 @@ static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
 
 	/*
 	 * Deep color support mandates RGB444 support for all video
-	 * modes and forbids YCRCB422 support for all video modes per
-	 * HDMI 1.3 spec.
+	 * modes.
 	 */
-	info->color_formats = DRM_COLOR_FORMAT_RGB444;
+	info->color_formats |= DRM_COLOR_FORMAT_RGB444;
 
 	/* YCRCB444 is optional according to spec. */
 	if (hdmi[6] & DRM_EDID_HDMI_DC_Y444) {
-- 
2.33.1