Thread (172 messages) 172 messages, 9 authors, 2021-10-04
STALE1736d REVIEWED: 3 (0M)

[PATCH 5.14 142/162] drm/amd/display: Link training retry fix for abort case

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-09-27 17:30:32
Also in: lkml
Subsystem: amd display core, drm drivers, radeon and amdgpu drm drivers, the rest · Maintainers: Harry Wentland, Leo Li, David Airlie, Simona Vetter, Alex Deucher, Christian König, Linus Torvalds

From: Meenakshikumar Somasundaram <redacted>

[ Upstream commit 71ae30997a8f1791835167d3ceb8d1fab32407db ]

[Why]
If link training is aborted, it shall be retried if sink is present.

[How]
Check hpd status to find out whether sink is present or not. If sink is
present, then link training shall be tried again with same settings.
Otherwise, link training shall be aborted.

Reviewed-by: Jimmy Kizito <redacted>
Acked-by: Mikita Lipski <redacted>
Signed-off-by: Meenakshikumar Somasundaram <redacted>
Tested-by: Daniel Wheeler <redacted>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
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 a6d0fd24fd02..83ef72a3ebf4 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
@@ -1849,9 +1849,13 @@ bool perform_link_training_with_retries(
 		dp_disable_link_phy(link, signal);
 
 		/* Abort link training if failure due to sink being unplugged. */
-		if (status == LINK_TRAINING_ABORT)
-			break;
-		else if (do_fallback) {
+		if (status == LINK_TRAINING_ABORT) {
+			enum dc_connection_type type = dc_connection_none;
+
+			dc_link_detect_sink(link, &type);
+			if (type == dc_connection_none)
+				break;
+		} else if (do_fallback) {
 			decide_fallback_link_setting(*link_setting, &current_setting, status);
 			/* Fail link training if reduced link bandwidth no longer meets
 			 * stream requirements.
-- 
2.33.0


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