Bug#929834: Buster/XFCE unlock screen is blank

[John Franklin <franklin@sentaidigital.com>]

On Sat, 1 Jun 2019 06:16:58 +0530 Raj Kiran Grandhi <
grajkiran@gmail.com> wrote:
> Hi,
> 
> In a fresh install of Buster with XFCE desktop, locking the screen
> blanks the monitor and the monitor enters a power save state. After
> that, neither moving the mouse nor typing on the keyboard would turn
> the monitor back on.
> I could find two ways to get the display back on:
> 
> 1. Typing the password without any visual feedback (while the monitor
> continues to be in the power save state) unlocks the screen and the
user
> session is displayed normally.
> 
> 2. Switching to another VT, say vt1 or vt2 turns the monitor back on
> and on switching
> back to the vt of the original session the unlock prompt is displayed
> normally and the screen can be unlocked.
> 

I've been suffering from this bug in a clean Buster system, too.  A
solution noted in another bug tracker is to explicitly tell X.org to
use the intel driver.  Apparently, it uses the fbdev driver by default.
(Sorry, I don't have a reference to other bug handy.)  

Per a suggestion in the other bug, I added the following config about a
week ago and haven't seen the problem since.

$ cat /etc/X11/xorg.conf.d/20-intel.conf 
Section "Device"
  Identifier	"Intel Graphics"
  Driver	"intel"
EndSection

jf
-- 
John Franklin <franklin@sentaidigital.com>