Reposting the bisection in a form that survives whitespace collapsing - the 
table in
the description lost its column alignment. Each value is labelled here.

Config 1 - stock (Panel Replay ON, VRR ON):
  selective-fetch failures 1, PSR idle timeouts 14, FIFO underruns 2, ATS 
faults 10
  -> DISPLAY CORRUPTED

Config 2 - xe.enable_psr2_sel_fetch=0 (Panel Replay ON, VRR ON):
  selective-fetch failures 0, PSR idle timeouts 3, FIFO underruns 1, ATS faults 0
  -> DISPLAY CORRUPTED

Config 3 - xe.enable_psr=0 xe.enable_panel_replay=0 (Panel Replay OFF, VRR ON):
  selective-fetch failures 0, PSR idle timeouts 0, FIFO underruns 0, ATS faults 0
  -> OK

Config 4 - xe.enable_panel_replay=0 (Panel Replay OFF, VRR OFF):
  selective-fetch failures 0, PSR idle timeouts 0, FIFO underruns 0, ATS faults 0
  -> OK

Each configuration was tested with the same reproduction: several minutes of
fullscreen video, entering and exiting fullscreen repeatedly. Counts are from
"journalctl -b -k" for the corresponding boot.

Conclusions:

1. Panel Replay is enabled in both failing configurations and disabled in both
   working ones.

2. Config 3 is the key data point: Panel Replay OFF was stable while VRR was 
still
   ON. VRR alone is therefore not sufficient to trigger the failure. Panel 
Replay is
   the necessary ingredient.

3. PSR itself is not at fault. Config 4 leaves PSR fully enabled and is stable, 
so a
   Panel Replay quirk for this panel is sufficient - disabling PSR wholesale 
would
   cost power saving for no reason.

4. "Selective fetch area calculation failed in pipe A" is present at boot in the
   working configuration too, so it appears unrelated to the corruption.

I am happy to test patches or collect additional debugfs output on this
hardware.

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2163125

Title:
  drm/xe Panther Lake: DP Panel Replay causes display corruption on
  Samsung ATNA40HQ09-0 (ThinkPad X1 Carbon Gen 14)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2163125/+subscriptions


-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to