xrandr shows monitor connected but autorandr always switches back (ext. monitor screen stays black)

[MartyMcFlyInTheSky]

Autorandr works great for my external monitor at home, but at work I have the following issue:

• Without autorandr: If I come to work in the morning the screen stays black even after applying my settings (saved from arandr). xrandr does however pick up the screen as an output even if it's black. So it seems to be some kind of a standby-mode that will not react to HDMI output. To make it work I always have to manually press the some buttons on the monitor to "wake it up". The monitor is a Samsung LS32A800NMPXEN. Any idea what the problem is here?

• With autorandr: Above issue also seems to influence the behavior of autorandr, because once I plug the monitor in it tries to apply the saved setting for the external Samsung monitor (which it detects), however then it immediately switches back for reasons I don't understand. I have hooked the postswitch with

notify-send -i display "Display profile" "$AUTORANDR_CURRENT_PROFILE"

to check that this is what is actually going on and it confirms above assumption.

I'm not an expert in monitors, but maybe someone could point me into the right direction. The optimal solution would be for the monitor to immediately start streaming once I plug in the HDMI cable ( which is the case for my home monitor (Alienware)). Are there known issues like this with some samsung screens or is this unrelated?

Furthermore I'd like to understand where this switching forth and back behavior is coming from. Does autorandr react on other triggers than just HDMI plugged in?

[phillipberndt]

I'm facing the same problem myself, and for me, the reason is that the graphics driver and monitor don't play well together, especially if multiple screens are connected via daisy chaining. Upgrading to the latest OS (Ubuntu 20.04 -> 24.04 in my case) allegedly helps a lot.

I haven't found a good workaround without upgrading, I so far just retry until it works.

I haven't tried systematically sending dpms comments to the black screens. (xset dpms force ..)

[MartyMcFlyInTheSky]

@phillipberndt I heard that graphics cards are always a bit of a problem on linux, but I'm happy to hear that this got better with the new Ubuntu (I'm currently using 22.04). So I'm going to try to update soon. What are dpms comments?