[Hardware] Monitor is not detected after monitor power cycle

[kerryhall]

Brand new fresh install of Debian 12.

I have a Geforce 1060 GTX, but wanting to run ML workloads that require more RAM, I recently got a P40. Everything works great, the P40 is excellent, but running into a very strange issue now.

When I turn off my monitor and back on, the monitor no longer has output going to it from my video card. If I unplug the HDMI connector and plug it back in, I get video on the monitor again, but it looks like a lot my windows are off screen. I then have to load up nvidia-settings and set the resolution back to 3840x2160, and refresh rate to 60 hz. Then I get all my windows back. When I'm actively using my computer, those two settings correctly stay at 3840x2160 / 60 hz, but only when I power cycle my monitor do they revert to "auto". I'm not sure how nvidia settings is detecting my monitor is off and then deciding to change the video output settings for no reason, it's very strange.

nvidia settings also shows the p40 as "nvidia vgx (disabled)". I'm wondering if somehow some software thinks my desktop should be extended to the p40, despite it not having a video output and me only having one monitor.

How do I convince nvidia-settings to always send output to hdmi, and keep the resolution at 4k 60hz?

[mrmazda]

Are you sure it's not Xorg or your DE mis-doing the deed rather than NVidia? Which DE? If using Plasma, try disabling KScreen2 in automatic startup. Multiple powers trying to control the same object is a recipe for frustration.