I am hoping to find a solution to this very annoying issue. I turned on my PC today and noticed that only my VGA monitor was detected, which is odd because just last night both monitors were working normal. The other issue is that the monitor that does work will only allow me to have 640 X 480 resolution.
Things I have tried:
Switching from Nvidia drivers to Xorg.
Purging and reinstalling Nvidia
Rebooting several times
Adding monitors in the terminal with Xrandr (When I do this it gives me "Failed to get size of gamma for output defaults")
Yesterday I was tinkering around a bit with Wine and PlayOnLinux, but I am not sure if that is what caused this issue. When I go to the monitor settings it only shows my VGA monitor, and will not let me change the resolution. I was originally allowed to change the resolutions of the HDMI and VGA monitors with no problem.
Let me know what other information I can provide to help fix this issue.
Following the advice of a commenter I tried
dmsg | grep -i nvidia and got this output:
[ 2.522071] nvidia: module license 'NVIDIA' taints kernel. [ 2.530529] nvidia: module verification failed: signature and/or required key missing - tainting kernel [ 2.537250] nvidia-nvlink: Nvlink Core is being initialized, major device number 247 [ 2.537639] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 384.98 Thu Oct 26 15:16:01 PDT 2017 (using threaded interrupts) [ 2.539046] nvidia-modeset: Loading NVIDIA Kernel Mode Setting Driver for UNIX platforms 384.98 Thu Oct 26 14:41:13 PDT 2017 [ 2.539722] [drm] [nvidia-drm] [GPU ID 0x00000100] Loading driver [ 13.660397] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card1/input5 [ 13.660463] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card1/input6 [ 13.660530] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card1/input7
lspci -v | grep -i nvidia I get:
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GT 640] (rev a1) (prog-if 00 [VGA controller])
Kernel driver in use: nvidia
Kernel modules: nvidiafb, nouveau, nvidia_384_drm, nvidia_384
01:00.1 Audio device: NVIDIA Corporation GK107 HDMI Audio Controller (rev a1)