This is a note to let you know that I've just added the patch titled
drm/amd/display: Fix DP MST sinks removal issue
to the 6.2-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-sinks-removal-issue.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a77829221c26b60db4665f9d53458d4ec36b5124
Author: Cruise Hung <Cruise.Hung@xxxxxxx>
Date: Wed Mar 22 17:08:41 2023 -0500
drm/amd/display: Fix DP MST sinks removal issue
[ Upstream commit cbd6c1b17d3b42b7935526a86ad5f66838767d03 ]
[Why]
In USB4 DP tunneling, it's possible to have this scenario that
the path becomes unavailable and CM tears down the path a little bit late.
So, in this case, the HPD is high but fails to read any DPCD register.
That causes the link connection type to be set to sst.
And not all sinks are removed behind the MST branch.
[How]
Restore the link connection type if it fails to read DPCD register.
Cc: stable@xxxxxxxxxxxxxxx
Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Wenjing Liu <Wenjing.Liu@xxxxxxx>
Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx>
Signed-off-by: Cruise Hung <Cruise.Hung@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
(cherry picked from commit cbd6c1b17d3b42b7935526a86ad5f66838767d03)
Modified for stable backport as a lot of the code in this file was moved
in 6.3 to drivers/gpu/drm/amd/display/dc/link/link_detection.c.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index 754fc86341494..54656fcaa6464 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1016,6 +1016,7 @@ static bool detect_link_and_local_sink(struct dc_link *link,
struct dc_sink *prev_sink = NULL;
struct dpcd_caps prev_dpcd_caps;
enum dc_connection_type new_connection_type = dc_connection_none;
+ enum dc_connection_type pre_connection_type = link->type;
const uint32_t post_oui_delay = 30; // 30ms
DC_LOGGER_INIT(link->ctx->logger);
@@ -1118,6 +1119,8 @@ static bool detect_link_and_local_sink(struct dc_link *link,
}
if (!detect_dp(link, &sink_caps, reason)) {
+ link->type = pre_connection_type;
+
if (prev_sink)
dc_sink_release(prev_sink);
return false;
@@ -1349,6 +1352,8 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
bool is_delegated_to_mst_top_mgr = false;
enum dc_connection_type pre_link_type = link->type;
+ DC_LOGGER_INIT(link->ctx->logger);
+
is_local_sink_detect_success = detect_link_and_local_sink(link, reason);
if (is_local_sink_detect_success && link->local_sink)
@@ -1359,6 +1364,10 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
link->dpcd_caps.is_mst_capable)
is_delegated_to_mst_top_mgr = discover_dp_mst_topology(link, reason);
+ DC_LOG_DC("%s: link_index=%d is_local_sink_detect_success=%d pre_link_type=%d link_type=%d\n", __func__,
+ link->link_index, is_local_sink_detect_success, pre_link_type, link->type);
+
+
if (is_local_sink_detect_success &&
pre_link_type == dc_connection_mst_branch &&
link->type != dc_connection_mst_branch)
