Bug#929834: Buster/XFCE unlock screen is blank

[Russ Allbery <rra@debian.org>]

Yves-Alexis Perez <corsac@debian.org> writes:

> Actually it seems to me that the bug is a bad interaction with light-
> locker/lightdm locking system (which relies on vt switch) and the Intel
> driver. It only seems to happens on this driver, and I think it's also
> been reproduced just by doing vt-switches (but can't remember where it
> was reported).

Ah, good call.  I was also seeing other problems with the Intel driver in
combination with light-locker where the monitor resolution would be set to
some incorrect value after restore from lock.  This would come with kernel
errors like:

[drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe B
[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun

and then lots and lots of:

[drm:intel_dp_start_link_train [i915]] *ERROR* Timed out waiting for DP idle patterns

-- 
Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>