Need help to dig into X11 display freezing (Renoir, Xen/QubesOS)

[Yann Dirson]

Hello there,

For a few months I've been experiencing occasional freezes of the X11 display
on my QubesOS RENOIR laptop.  The setup is pretty much standard for QubesOS,
with both GPUs attached to dom0 and XFCE running there (and the dGPU being
mostly not used).  Kernel is QubesOS' kernel-latest-6.15.4.

Those freezes most often occur while the screen is blanked
by xscreensaver (suspend options fully deactivated here, as suspend is broken
on this platform): in this case moving the mouse does not get the unlock banner
displayed, the screen stays black... except the mouse pointer is visible.  I can
also switch to other virtual consoles and interact with the system, but was
never able to collect any evidence of something wrong being detected.

Occasionally it also happens (like yesterday) while I'm working, and the X11
display just seems frozen, no clue if the input devices trigger anything in
there.

I guess something goes wrong but gets undetected by the driver.  Any suggestion
as to extra logging/debug features to enable?

Best regards,
-- 
Yann