github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-13 15:40:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

drm/amd/display: Exit IPS before connector detection on resume

Browse Source 
[Why & How]
On resume, dm_resume() walks the connector list and, for each connector,
calls dc_link_detect_connection_type() at the top of the loop iteration
before the per-connector dc_exit_ips_for_hw_access() that sits in the
detection branch. There is no dc_exit_ips_for_hw_access() before the loop,
so the very first HW access relies on an earlier connector having already
taken the display out of IPS.

Commit d1d51519bc ("drm/amd/display: Skip eDP detection when no sink")
skips the eDP connector when no panel is present. On a DCN3.5 APU whose
eDP link has no sink, the eDP iteration - which used to bring the HW out
of IPS first - is now skipped, so a downstream DP connector becomes the
first one processed. Its initial DDC/AUX access then runs while the HW is
still idle, the AUX transfers time out (-ETIMEDOUT), and the EDID read
fails:

  [drm:dm_helpers_read_local_edid [amdgpu]] *ERROR* EDID err: 2, on connector: DP-1
  amdgpu: [drm] *ERROR* No EDID read.

Take the display out of IPS once before the detection loop so the first
connector processed no longer touches the AUX/DDC engine while the HW is
still in idle power state. This keeps the eDP-skip boot/resume
optimization while fixing the DP EDID read failure.

Fixes: d1d51519bc ("drm/amd/display: Skip eDP detection when no sink")
Reviewed-by: Roman Li <roman.li@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 86420fe3093161971b4064e05be11ffff1df76aa)
Cc: stable@vger.kernel.org
This commit is contained in:
Fangzhi Zuo 2026-08-27 13:12:46 -04:00 committed by Alex Deucher
parent 2e8ff3ac79
commit 3001d2073d
1 changed files with 4 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
View File

@ -1972,6 +1972,10 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
/* On resume we need to rewrite the MSTM control bits to enable MST*/
s3_handle_mst(ddev, false);
/* Exit IPS before the detection loop's first AUX/DDC access. */
scoped_guard(mutex, &dm->dc_lock)
dc_exit_ips_for_hw_access(dm->dc);
/* Do detection*/
drm_connector_list_iter_begin(ddev, &iter);
drm_for_each_connector_iter(connector, &iter) {