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Message-ID: <20240728154230.2046786-3-sashal@kernel.org>
Date: Sun, 28 Jul 2024 11:40:27 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Michael Strauss <michael.strauss@....com>,
Wenjing Liu <wenjing.liu@....com>,
Aurabindo Pillai <aurabindo.pillai@....com>,
Daniel Wheeler <daniel.wheeler@....com>,
Alex Deucher <alexander.deucher@....com>,
Sasha Levin <sashal@...nel.org>,
harry.wentland@....com,
sunpeng.li@....com,
Rodrigo.Siqueira@....com,
christian.koenig@....com,
Xinhui.Pan@....com,
airlied@...il.com,
daniel@...ll.ch,
hansen.dsouza@....com,
stylon.wang@....com,
amd-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.10 03/34] drm/amd/display: Add delay to improve LTTPR UHBR interop
From: Michael Strauss <michael.strauss@....com>
[ 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@....com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@....com>
Signed-off-by: Michael Strauss <michael.strauss@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
.../dc/link/hwss/link_hwss_hpo_fixed_vs_pe_retimer_dp.c | 5 +++++
1 file changed, 5 insertions(+)
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 3e6c7be7e2786..5302d2c9c7607 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
@@ -165,7 +165,12 @@ 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,
--
2.43.0
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