Mouse pointer disappears when using HDMI, not DVI

[winn]

OK so I have no idea what's going on here... I'm running Debian 9, with KDE Plasma 5.8.6, and haven't had any issues for many months on this system. Last night, I plugged it into my TV for the first time using HDMI, and that worked fine. However, when screen went into "sleep" mode it changed from 4K resolution to 640x480 and the mouse cursor disappeared. I rebooted, thinking it would reset the display, but it didn't.

I then moved the HDMI cable from my TV to my usual monitor, and the resolution was detected fine, but still no mouse cursor. The mouse is listed when I type this, though:

Code: Select all

xinput list

I tried disabling/enabling it using xinput, to no avail. On a whim, I swapped the HDMI cable for a DVI cable, and VOILA, mouse pointer is back. I plugged in the TV (HDMI) and monitor (DVI) simultaneously, and the mouse pointer can move from one to the other no problem.

However, when I unplug the DVI, the mouse cursor disappears again (and the screen resizes for the TV, but not the normal monitor).

I suspect the culprit here might be the proprietary NVIDIA GPU drivers, which I installed earlier this week to do some GPU-accelerated computing tasks, but I'm not sure how that could be the case, or what steps I should take to fix this.

Any suggestions?

[winn]

I'm not sure why this worked, but I went into the UEFI and changed the default graphics from PCIE to onboard graphics and rebooted. The x-server failed to launch correctly (just a blank screen), so I rebooted again, switched back to PCIE, and then it went fine on next reboot, mouse pointer shows up OK with only HDMI display attached now.