I have a Dell Latitude Laptop running Ubuntu 22.04 (this is my second laptop with this issue, the other one was running Ubuntu 18.04). On this laptop I connect a second screen with a usb-c hub adapter which has an HDMI input port, then in some weird cases, the screen of the second monitor goes black for a few second then comes back to life. During this time, the monitor still seems connected (I can still interact with windows open on the screen). My monitor prints a "no signal" popup, it looks like it is disconnected then reconnected although from the computer I can still browse it as if it was on.
I noticed 2 way of triggering this : a meeting call in MS Teams and when calling xrandr from a terminal.
The connection through the usb-c hub seems to be with altDisplayPort as the monitor appears under "DP1" in xrandr. When I connect the monitor with the HDMI port on the laptop, it causes no issue which leads me to think that the hub or the altDisplayPort driver/configuration may be at fault here.
If anyone has any hindsight on what I can try to fix this, it would be great.
uname -a
Linux name 5.15.0-56-generic #62-Ubuntu SMP Tue Nov 22 19:54:14 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Xrandr output:
Screen 0: minimum 320 x 200, current 3840 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 309mm x 174mm
1920x1080 60.05*+ 60.01 59.97 59.96 59.93 48.04
1680x1050 59.95 59.88
1400x1050 59.98
1600x900 59.99 59.94 59.95 59.82
1280x1024 60.02
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1280x800 59.99 59.97 59.81 59.91
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
700x525 59.98
800x450 59.95 59.82
640x512 60.02
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 527mm x 296mm
1920x1080 60.00*+ 120.00 119.88 119.98 99.93 72.00 50.00 59.94
1680x1050 59.88
1280x1024 75.02 60.02
1440x900 59.90
1280x720 60.00 50.00 59.94
1024x768 119.99 75.03 70.07 60.00
832x624 74.55
800x600 119.97 72.19 75.00 60.32 56.25
720x480 60.00 59.94
640x480 75.00 72.81 66.67 60.00 59.94
720x400 70.08
HDMI-2 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-3 disconnected (normal left inverted right x axis y axis)
