Solution: SDDM - Flickering with External Monitor Connected (Intel UHD 620)

English Hardware
1

Just dropping this here, in case someone else experiences the same issue.

Hardware: HP 840 G5 / Intel UHD Graphics 620
OS: Latest Tumbleweed
Symptom: When external monitor is connected, SDDM is flickering, input isn’t always registered, login doesn’t work (screen gets black).
Workaround: Disconnect external monitor on startup, plugin after login.
Solution:

  1. Install xf86-video-intel
  2. Add to /etc/X11/xorg.conf.d/50-device.conf:
Section "Device"
  Identifier "Intel Graphics"
  Driver "intel"
  Option "TearFree" "true"
EndSection
2

Thanks for sharing this.

3

For VGA, DP or HD_SDI it is ok, for HDMI you can burn out HDMI ports.

4

Seriously. I’ve had HDMI input port deaths 4 times and output port once, only 2 of which were covered under a warranty. :cry:

5

That’s interesting. Per tech specs, HDMI does support hotplugging. But I’d guess it’s badly designed; add to that bad/non-standard HDMI ports and I see how this could become an issue.

6

Since I can’t update the initial post (maybe a mod can help out?), here’s an updated version of the solution (previous one caused occasional flickering):

Hardware: HP 840 G5 / Intel UHD Graphics 620
OS: Latest Tumbleweed (20190412)
Symptom: When external monitor is connected via dock/DP, SDDM is flickering, input isn’t always registered, login doesn’t work (screen gets black).
Workaround: Disconnect external monitor on startup, plugin after login.
**Solution: **
Install xf86-video-intel
Create /etc/X11/xorg.conf.d/20-intel.conf and add:

Section "Device"
   Identifier "Intel Graphics"
   Driver "intel"
   Option "AccelMethod" "sna"
   Option "TearFree" "true"
   Option "DRI" "3"
   Option "Backlight" "intel_backlight"
EndSection

Cause: Intel drivers not installed & configured automatically, maybe due to an old bug in Xorg which causes flickering in fullscreen windows (not confirmed, just from what I gathered).