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

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[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>
This commit is contained in:
Fangzhi Zuo 2026-08-27 13:12:46 -04:00 • committed by Alex Deucher
commit 86420fe309
1 changed files with 4 additions and 0 deletions
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