Gentoo Archives: gentoo-user

From: Andreas Fink <finkandreas@×××.de>
To: gentoo-user@l.g.o
Subject: [gentoo-user] Strange behaviour disconnecting and reconnecting USB-C screen
Date: Tue, 11 Jan 2022 09:26:06
Message-Id: 20220111102544.6992b86f@anfink-laptop
1 Hello,
2 I've got a new laptop and see a strange behaviour when disconnecting
3 and reconnecting my USB-C screen.
4 Here are the steps that I am doing. I have a dual screen setup with
5 xrandr, with my notebook screen being the primary screen and a second
6 large external screen connected via USB-C to my notebook directly.
7 Now I disconnect the USB-C cable and do not do anything software wise,
8 i.e. my X-Server is still pretending to run on two screens, I can move
9 the screen outside of my notebook screen (into the area where the
10 external screen).
11 Now I reconnect the USB-C cable but the screens stays blank (the the
12 screen it says "No USB Type-C connection from your computer"). The only
13 way to get a signal again is to first use xrandr to only use my
14 notebook screen, and at the exact time udev gets a DRM event, and
15 suddently my external monitor appears within xrandr as connected (I did
16 not touch the cable, I only ran an xrandr command to use only the
17 notebook screen). Right after the DRM event I can run the xrandr
18 command to use both screens, but it is annoying to degrade first to one
19 screen, because all windows are moved around and I do not end up with
20 the same window setup as before.
22 Using the same screen with the same experiment as described above but
23 with a different notebook the screen is able to pick up the signal
24 again, so it's not purely a problem with the external screen.
25 Any idea what is going on and how I can workaround it? I just want to
26 disconnect the cable and reconnect it without the need to switch any
27 xrandr setup.
29 Thanks for your ideas and help
30 Andreas