drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/TODO b/drivers/accessibility/speakup/TODO
new file mode 100644
index 000000000..d4ca093bf
--- /dev/null
+++ b/drivers/accessibility/speakup/TODO
@@ -0,0 +1,22 @@
+Speakup project home:  http://www.linux-speakup.org
+
+Mailing List:  speakup@linux-speakup.org
+
+Speakup is a kernel based screen review package for the linux operating
+system.  It allows blind users to interact with applications on the
+linux console by means of synthetic speech.
+
+Currently, speakup has one issue we know of.
+
+It seems to only happen on SMP systems. It seems that text in the output buffer
+gets garbled because a lock is not set. This bug happens regularly, but no one
+has been able to find a situation which produces it consistently.
+
+Patches, suggestions, corrections, etc, are definitely welcome.
+
+We prefer that you contact us on the mailing list; however, if you do
+not want to subscribe to a mailing list, send your email to all of the
+following:
+
+okash.khawaja@gmail.com, w.d.hubbs@gmail.com, chris@the-brannons.com,
+kirk@reisers.ca and samuel.thibault@ens-lyon.org.