Bug#1050512: gnome-shell: Crash when viewing video with mpv

[Simon McVittie]

Control: tags -1 + moreinfo

On Thu, 31 Aug 2023 at 13:45:04 +0200, Marc Glisse wrote:
> It looks like my stack trace is useless because I forgot to set
> MUTTER_SYNC=1 :-(
>
> It seems likely that this is the same bug as
> https://gitlab.gnome.org/GNOME/mutter/-/issues/2857 (sadly not fixed yet).

Would you be able to reproduce this with MUTTER_SYNC=1 in the environment
(setting it in ~/.config/environment.d/mutter-sync.conf should apparently
work) to confirm that it's the same crash as mutter#2857 upstream?

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6778#note_1782883
seems like the characteristic backtrace: a BadMatch in response to
DPMSForceLevel().

You say this happens when playing a video with mpv: perhaps this could
be because mpv disables power saving / screen blanking while it's playing
the video?

If you install the x11-xserver-utils package and run "xset -dpms", does
that trigger the same crash?

There is a merge request upstream which *might* fix this. If you are able
to rebuild the mutter source package with patches applied, please try
applying the attached file "bug1050512-without-xsync.patch" and see whether
you can reproduce the crash. If that works, please report back. If not,
please revert that change, apply "bug1050512-with-xsync.patch", rebuild
and try again.

If you're not able to rebuild the mutter source package, I'll try to
prepare packages that you can try, but there's a heatwave here at the
moment, so I'm trying not to heat my house more by compiling lots of
packages right now!

Thanks,
    smcv
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