Bug#867555: gnome-shell: Tries to drive monitor at unsupported refresh rate

[Mark Brown]

On Fri, Jul 07, 2017 at 06:49:06PM +0100, Simon McVittie wrote:
> On Fri, 07 Jul 2017 at 13:20:28 +0100, Mark Brown wrote:

> > > * Move your ~/.config/monitors.xml out of the way (don't delete it; if
> > >   this works, it would be useful to see what's in it). This is where
> > >   GNOME stores display settings. You could also compare it with
> > >   ~/.config/monitors.xml~ which is the second-most-recent version.

> > Removing my monitors.xml appears to fix things, the difference appears
> > to be that if I try to make any change to the default layout of the
> > monitors monitor 1 goes blank.

> Thanks. It seems that the mode in which GNOME Shell brings up your
> displays when unconfigured is fine, but when you start reconfiguring
> (for which I assume you're using gnome-control-center, aka "Settings"?),
> some code that only runs during reconfiguration chooses an impossible
> mode. Hopefully this will be enough for someone more knowledgeable than
> me to narrow down which module has the problem.

This also happens during parsing of a preexisting copy of that file,
like I say this is something that has been working for a while and just
broke.

> > I'm using a default Debian system with systemd, I don't know how
> > specifically the X server is started. The X logs haven't been updated
> > for a long time.  There's no obvious X logs in .cache/gdm and I've no
> > idea how to get X logs from systemd.

> Please check /var/log/syslog (as root or a member of group adm), assuming
> you haven't removed rsyslogd. X logs go there via the systemd Journal;
> the Journal is in-memory-only by default, because writing it to disk
> is mostly redundant with having a syslogd.

I don't really know what I'm looking for in terms of display server
output in those logs, though I do see a few of these:

Jul 10 11:22:02 debutante gnome-shell[2360]: Failed to apply DRM plane transform 0: Invalid argument
Jul 10 11:22:02 debutante gnome-shell[2360]: Failed to apply DRM plane transform 0: Invalid argument
Jul 10 11:22:02 debutante gnome-shell[2360]: Failed to apply DRM plane transform 0: Invalid argument
Jul 10 11:22:03 debutante kernel: [  618.626812] [drm:cypress_dpm_set_power_state [radeon]] *ERROR* rv770_restrict_performance_levels_before_switch failed
Jul 10 11:22:04 debutante kernel: [  619.256880] [drm:cypress_dpm_set_power_state [radeon]] *ERROR* rv770_restrict_performance_levels_before_switch failed

so perhaps this is a kernel change.

> If you are intentionally living in the future, someone who knows more
> about the DRI/DRM stack than I do will have to tell you what the

Well, I'm just randomly changing settings in the hope that I can
persuade something to not render my primary development sysetm
unusuable.  I'm definitely running Wayland on my laptop as there's been
some previous issue which completely prevented login with X11 but it
seemed to work fine with Wayland but on this system I don't really care
(I've not noticed any problems).

> Wayland equivalent of xrandr is. Rummaging in /sys/class/drm/card*/modes,
> or using parse-edid < /sys/class/drm/cardwhatever/edid (parse-edid is
> in the read-edid package), might be informative?

I don't appear to have a parse-edid installed.
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