This is a note to let you know that I've just added the patch titled
drm/amd/display: Add delay to improve LTTPR UHBR interop
to the 6.6-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-add-delay-to-improve-lttpr-uhbr-inte.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit aba5c0e112abf667157b347a72bb37439c974b5c
Author: Michael Strauss <michael.strauss@xxxxxxx>
Date: Tue Apr 9 12:00:34 2024 -0400
drm/amd/display: Add delay to improve LTTPR UHBR interop
[ Upstream commit 10839ee6a977ed1f7d0f4deb29f2d7e5d1f2a9dd ]
[WHY]
Avoid race condition which puts LTTPR into bad state during UHBR LT.
[HOW]
Delay 30ms between starting UHBR TPS1 PHY output and sending TPS1 via DPCD.
Reviewed-by: Wenjing Liu <wenjing.liu@xxxxxxx>
Acked-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Michael Strauss <michael.strauss@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/link/hwss/link_hwss_hpo_fixed_vs_pe_retimer_dp.c b/drivers/gpu/drm/amd/display/dc/link/hwss/link_hwss_hpo_fixed_vs_pe_retimer_dp.c
index b621b97711b61..a7f5b0f6272ce 100644
--- a/drivers/gpu/drm/amd/display/dc/link/hwss/link_hwss_hpo_fixed_vs_pe_retimer_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/link/hwss/link_hwss_hpo_fixed_vs_pe_retimer_dp.c
@@ -162,7 +162,12 @@ static void set_hpo_fixed_vs_pe_retimer_dp_link_test_pattern(struct dc_link *lin
link_res->hpo_dp_link_enc->funcs->set_link_test_pattern(
link_res->hpo_dp_link_enc, tp_params);
}
+
link->dc->link_srv->dp_trace_source_sequence(link, DPCD_SOURCE_SEQ_AFTER_SET_SOURCE_PATTERN);
+
+ // Give retimer extra time to lock before updating DP_TRAINING_PATTERN_SET to TPS1
+ if (tp_params->dp_phy_pattern == DP_TEST_PATTERN_128b_132b_TPS1_TRAINING_MODE)
+ msleep(30);
}
static void set_hpo_fixed_vs_pe_retimer_dp_lane_settings(struct dc_link *link,
