diff options
| author | Nicolas Frattaroli <nicolas.frattaroli@collabora.com> | 2026-06-09 14:43:56 +0200 |
|---|---|---|
| committer | Daniel Stone <daniels@collabora.com> | 2026-06-09 21:03:51 +0100 |
| commit | f532dc0ea55a25dd24a79442fd0348da09b04b72 (patch) | |
| tree | cf169bf76be32c44ebb96102d74e49d9bff21da9 | |
| parent | cb5c6b7e7b71299adfd0d33411048bf5561740a2 (diff) | |
| download | linux-f532dc0ea55a25dd24a79442fd0348da09b04b72.tar.gz linux-f532dc0ea55a25dd24a79442fd0348da09b04b72.zip | |
drm/display: hdmi-state-helper: Try subsampling in mode_valid
drm_hdmi_connector_mode_valid assumes modes are only valid if they work
with RGB. The reality is more complex however: YCbCr 4:2:0
chroma-subsampled modes only require half the pixel clock that the same
mode would require in RGB.
This leads to drm_hdmi_connector_mode_valid rejecting perfectly valid
420-only or 420-also modes.
Fix this by checking whether the mode is 420-capable first. If so, then
proceed by checking it with DRM_OUTPUT_COLOR_FORMAT_YCBCR420 so long as
the connector has legalized 420, otherwise error out. If the mode is not
420-capable, check with RGB as was previously always the case.
Fixes: 47368ab437fd ("drm/display: hdmi: add generic mode_valid helper")
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://patch.msgid.link/20260609-color-format-v17-9-35739b5782cc@collabora.com
Signed-off-by: Daniel Stone <daniels@collabora.com>
| -rw-r--r-- | drivers/gpu/drm/display/drm_hdmi_state_helper.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index 069f9bf2489e..ce17eeefc2da 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -943,8 +943,21 @@ drm_hdmi_connector_mode_valid(struct drm_connector *connector, const struct drm_display_mode *mode) { unsigned long long clock; + enum drm_output_color_format fmt; + + if (drm_mode_is_420_only(&connector->display_info, mode)) { + if (connector->ycbcr_420_allowed) + fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR420; + else + return MODE_NO_420; + } else if (drm_mode_is_420_also(&connector->display_info, mode) && + connector->ycbcr_420_allowed) { + fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR420; + } else { + fmt = DRM_OUTPUT_COLOR_FORMAT_RGB444; + } - clock = drm_hdmi_compute_mode_clock(mode, 8, DRM_OUTPUT_COLOR_FORMAT_RGB444); + clock = drm_hdmi_compute_mode_clock(mode, 8, fmt); if (!clock) return MODE_ERROR; |