[Bug 112351] New: Wayland Weston & Sway - vsync stutters in mpv on Intel graphics

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=112351

            Bug ID: 112351
           Summary: Wayland Weston & Sway - vsync stutters in mpv on Intel
                    graphics
           Product: DRI
           Version: DRI git
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: not set
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: tempel.julian at gmail.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

Created attachment 146003
  --> https://bugs.freedesktop.org/attachment.cgi?id=146003&action=edit
dmesg log of the test system

Originally reported here, but posting here in case it might be a kernel issue:
https://gitlab.freedesktop.org/mesa/mesa/issues/2048

The issue: Stutter free video playback is not possible on Gemini Lake with
Wayland compositors.

To reproduce, run mpv 0.30 via
"mpv --no-config --video-sync=display-resample --hwdec=vaapi
http://www.oc-burner.de/ftp/Videos/juddertest/juddertest_60.mp4" 

on a ~60Hz display in a Weston or Sway Wayland session (mpv automatically uses
native Wayland windowing, no xwayland involved). There is stutter each few
seconds, thus mpv's statistics recognize vsync jitter spikes and in the wake
mistimed or delayed frames (either watch mpv's terminal output or enable LUA
stats via Shift + i).

There is no stutter with xf86-video-intel DDX on Xserver (also not in
fullscreen with pageflipping triggered). There is also no stutter with AMD GPU
on Wayland, so the root of the issue should not lie in mpv.
modesetting DDX on Xserver shows a very similar (if not exactly the same?)
issue as Wayland with Intel graphics, if that's important. Though there
probably is xf86-video-intel for a good reason, so perhaps the Wayland
situation is more deserving of attention.

Issue also ocurs with --hwdec=vaapi-copy, which uses the same windowing context
as software decoding.

Tested on
Arch Linux / Manjaro 5.3.8
xorg 1.20.5-4 from Arch/Manjaro repo
Weston 7.0.0
recent sway-git/wlroots-git which supports correct vsync presentation feedback

Attaching a dmesg log of the test system.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20191120/de658941/attachment.html>