MST configuration breaks after resume with monitor switched to different source
Submitted by Simon Richter
Assigned to Intel GFX Bugs mailing list
Link to original bug (#112400)
Description
I use a MST based dual monitor setup where the first monitor in the chain has multiple inputs and allows me to switch between input sources.
When switching away from my Linux box, there is a good chance that afterwards the configuration will be invalid, and after switching back, no picture will be shown.
I usually hibernate the machines at night, and resuming with the monitor switched to the other source always triggers this condition (while switching away during normal operation only has a high probability).
Hibernating again and making sure to boot up with the monitor set to the right source does not fix the problem -- the firmware correctly shows the logo on both monitors, a text mode screen with a blinking cursor is shown during resume, then the invalid configuration is reloaded.
Attached kernel log is with a Debian standard kernel,
Linux debian 4.19.0-6-amd64 #1 (moved) SMP Debian 4.19.67-2+deb10u1 (2019-09-20) x86_64 GNU/Linux
- Normal boot
- X start
- hibernate
- resume
- X shutdown
- X restart