[PATCH AUTOSEL 6.12 158/486] drm/amd/display: not abort link train when bw is low

Sasha Levin sashal at kernel.org
Mon May 5 22:33:54 UTC 2025


From: Peichen Huang <PeiChen.Huang at amd.com>

[ Upstream commit 8a21da2842bb22b2b80e5902d0438030d729bfd3 ]

[WHY]
DP tunneling should not abort link train even bandwidth become
too low after downgrade. Otherwise, it would fail compliance test.

[HOW}
Do link train with downgrade settings even bandwidth is not enough

Reviewed-by: Cruise Hung <cruise.hung at amd.com>
Reviewed-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram at amd.com>
Signed-off-by: Peichen Huang <PeiChen.Huang at amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 .../gpu/drm/amd/display/dc/link/protocols/link_dp_training.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
index 27b881f947e8b..9385a32a471b8 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
@@ -1769,13 +1769,10 @@ bool perform_link_training_with_retries(
 			is_link_bw_min = ((cur_link_settings.link_rate <= LINK_RATE_LOW) &&
 				(cur_link_settings.lane_count <= LANE_COUNT_ONE));
 
-			if (is_link_bw_low) {
+			if (is_link_bw_low)
 				DC_LOG_WARNING(
 					"%s: Link(%d) bandwidth too low after fallback req_bw(%d) > link_bw(%d)\n",
 					__func__, link->link_index, req_bw, link_bw);
-
-				return false;
-			}
 		}
 
 		msleep(delay_between_attempts);
-- 
2.39.5



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