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pop-os / pop

A project for managing all Pop!_OS sources
https://system76.com/pop
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External monitors (sometimes) not detected #1358

Open dmuensterer opened 4 years ago

dmuensterer commented 4 years ago

Issue/Bug Description: The external monitors are sometimes not detected when booting up. They are shown as disconnected when checking the xrandr output: when booting up 

DP-1-1 disconnected (normal left inverted right x axis y axis)
HDMI-1-1 disconnected (normal left inverted right x axis y axis)
DP-1-2 disconnected (normal left inverted right x axis y axis)
HDMI-1-2 disconnected (normal left inverted right x axis y axis)

My setup Dell XPS 15 9550 with Nvidia hybrid graphics. Dell WD19 TB Dockingstation with two connected monitors via DP and HDMI

Steps to reproduce (if you know): I could not find heuristics as to when it works and when it doesn't. It seems like a random chance if the monitors are detected on startup or not. If they are detected on startup, they work perfectly fine until the next shutdown/reboot.

Expected behavior: When connecting external displays they should be detected by the kernel and be usable.

Other Notes: I am using version 20.04 with the proprietary Nvidia drivers.

pahofmann commented 4 years ago

I have the same problem (XPS 9500 and WD19TB), but it started after upgrading to 20.10 for me.
It seems to be related to the 5.8 Kernel, when I boot with Kernel 5.4.0 everything works as expected.

dmuensterer commented 4 years ago

Thanks for the information, I can confirm that it works perfectly fine using the 5.4.0 Kernel. I also guess it is no coincidence we are both using Dell Hardware. Is there anyone who found the specific problem in the new kernels?