This is a note to let you know that I've just added the patch titled
drm/amd/display: Fix DP MST timeslot issue when fallback happened
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-fix-dp-mst-timeslot-issue-when-fallb.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 426328c1ce000b762bb03b5e2b6ded75c6e67f49
Author: Cruise Hung <Cruise.Hung@xxxxxxx>
Date: Thu Sep 8 22:04:09 2022 +0800
drm/amd/display: Fix DP MST timeslot issue when fallback happened
[ Upstream commit 20c6168b3c8aadef7d2853c925d99eb546bd5e1c ]
[Why]
When USB4 DP link training failed and fell back to lower link rate,
the time slot calculation uses the verified_link_cap.
And the verified_link_cap was not updated to the new one.
It caused the wrong VC payload time-slot was allocated.
[How]
Updated verified_link_cap with the new one from cur_link_settings
after the LT completes successfully.
Reviewed-by: Jun Lei <Jun.Lei@xxxxxxx>
Acked-by: Wayne Lin <wayne.lin@xxxxxxx>
Signed-off-by: Cruise Hung <Cruise.Hung@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 0c52506b367d..b4203a812c4b 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -2857,8 +2857,14 @@ bool perform_link_training_with_retries(
skip_video_pattern);
/* Transmit idle pattern once training successful. */
- if (status == LINK_TRAINING_SUCCESS && !is_link_bw_low)
+ if (status == LINK_TRAINING_SUCCESS && !is_link_bw_low) {
dp_set_hw_test_pattern(link, &pipe_ctx->link_res, DP_TEST_PATTERN_VIDEO_MODE, NULL, 0);
+ /* Update verified link settings to current one
+ * Because DPIA LT might fallback to lower link setting.
+ */
+ link->verified_link_cap.link_rate = link->cur_link_settings.link_rate;
+ link->verified_link_cap.lane_count = link->cur_link_settings.lane_count;
+ }
} else {
status = dc_link_dp_perform_link_training(link,
&pipe_ctx->link_res,
