Bug#1125275: mutter: Black screen on an HDMI monitor after loading Gnome Wayland session on a laptop with AMD Radeon graphics

[Simon McVittie]

Control: reassign -1 src:mutter,src:gnome-shell
Control: found -1 mutter/48.7-0+deb13u1
Control: found -1 gnome-shell/48.7-0+deb13u1
Control: tags -1 + trixie moreinfo
Control: forwarded -1 https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/8983

On Sun, 11 Jan 2026 at 21:09:47 +0200, Nazik wrote:
>My laptop is connected to an external monitor via HDMI. When I boot it, i can see GDM login screen on the internal screen, and I can see GDM's gray background on the external monitor.
>All is ok here. But after I type login and password, both the external and internal screens are OFF, and I can't use my system. In Gnome Settings, I always turn off the internal screen.

Please check the system log (systemd Journal) for warning messages. I 
suspect that you will see this message, and perhaps others:

     Page flip failed: drmModeAtomicCommit: Invalid argument

If you do, then this is the same issue as a few other regression reports 
seen after the 13.3 update. Unfortunately I don't see this regression 
myself, which is going to make it more difficult to debug.

Please could you attach your ~/.config/monitors.xml and 
/var/lib/gdm3/.config/monitors.xml? (Replace serial numbers, etc. with 
**** if you would prefer, as long as it's obvious where you have 
edited.)

>I also checked if the issue happens in the prev. kernel 6.12.57. It also happens with the older kernel. I suspect there is a bug in mutter / gnome-shell, but I am not 100% sure.

If you use snapshot.debian.org to downgrade gnome-shell (only) to 
version 48.4-1~deb13u1 from Debian 13.2, similar to what is described in 
<https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1125273#15>, does 
that work around this bug? If yes, then that would confirm that this is 
a bug in gnome-shell, and not mutter.

You would probably have to downgrade the gnome-shell, gnome-shell-common 
and gnome-shell-extension-prefs packages.

Or, if you downgrade only the mutter packages (mutter-common, 
gir1.2-mutter-16, libmutter-16-0 and mutter-common-bin) to version 
48.4-2, while leaving gnome-shell at version 48.7-0+deb13u1, does *that* 
work around this bug? If yes, then that would mean it's a regression in 
mutter and not gnome-shell.

You've already confirmed this is not a kernel regression, which is very 
helpful; and Mesa wasn't updated in Debian 13.3, so probably it isn't 
that either.

Thanks,
     smcv