GTX 980 @ 384.90 refuses to recognise dual monitors on wakeup

So I started having this issue a few weeks ago when I first connected my other screen (not used it for a year or so, without issues however). Used Mint Cinnamon before, and currently on Ubuntu 17.10 x64. The issue only appears with the Nvidia drivers and when I have more than one screen connected (both screens are connected to the GTX980-card, one HDMI and one HDMI through a display port adapter, since the card only has one HDMI port).

The problem appears when I leave the machine and it blanks the screen. When I come back it refuses to wake up. Switching one screen to another HDMI/Display port will wake up that screen and switch it to primary. However the second screen remains dead until I restart the machine. No fiddling with CTRl+ALT+Fx seems to fix the issue.

Kernel: 4.13.0-16-generic #19-Ubuntu
Distro: Ubuntu 17.10 (fully updated as of writing this)
Nvidia drivers: 384.90 (via “additional drivers” in Ubuntu)
Screen primary: Asus MX279 (Via HDMI->Card)
Screen secondary: AOC E2476VWM6 (Via HDMI->DPAdapter->Card)

The syslog is spammed with the following when I try to wake up the machine, or when I disconnect/connect the HDMI cables. It should be noted that I reinstalled the system (to Ubuntu 17.10) yesterday evening, and after leaving the machine over night the below information had been spamming the log all night. The syslog size was > 50MB when I woke up in the morning.

Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): connected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): 165.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6d3b040 Gjs_ShowAppsIcon.dash-item-container] connect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6d3b040 Gjs_ShowAppsIcon.dash-item-container] disconnect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6d3b040 Gjs_ShowAppsIcon.dash-item-container] emit method
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): CRT-0: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): CRT-0: 400.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-0: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-0: Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-0: 330.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-1: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-1: 600.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-2: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-2: Internal DisplayPort
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-2: 960.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-3: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-3: Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-3: 165.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-4: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-4: Internal DisplayPort
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-4: 960.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-5: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-5: Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-5: 165.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-6: disconnected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-6: Internal DisplayPort
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): DFP-6: 960.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): connected
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): Internal TMDS
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-7): 165.0 MHz maximum pixel clock
Oct 25 13:13:23 Teresa /usr/lib/gdm3/gdm-x-session[1551]: (--) NVIDIA(GPU-0):
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6e98780 Gjs_ShowAppsIcon.dash-item-container] connect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6e98780 Gjs_ShowAppsIcon.dash-item-container] disconnect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6e98780 Gjs_ShowAppsIcon.dash-item-container] emit method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6b46440 Gjs_ShowAppsIcon.dash-item-container] connect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6b46440 Gjs_ShowAppsIcon.dash-item-container] disconnect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6b46440 Gjs_ShowAppsIcon.dash-item-container] emit method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6dfebf0 Gjs_ShowAppsIcon.dash-item-container] connect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6dfebf0 Gjs_ShowAppsIcon.dash-item-container] disconnect method
Oct 25 13:13:23 Teresa gnome-shell[1703]: WARNING: addSignalMethods is replacing existing [0x5568f6dfebf0 Gjs_ShowAppsIcon.dash-item-container] emit method

I have tried disabling Wayland and restarting, but with no change. The below threads are threads that I’ve read and attempted solutions mentioned with no change to the issue. They are possible duplicates or similar issues.

https://devtalk.nvidia.com/default/topic/1025477/linux/x-org-crashes-on-ubuntu-17-10-with-driver-nvidia-384-after-upgrade/

https://devtalk.nvidia.com/default/topic/901948/linux/gtx-970-355-11-on-fc22-refuses-to-recognize-tv-used-as-monitor-upon-display-sleep-resume-tv-resta/1

nvidia-bug-report.log.gz (381 KB)

Made another test where I let Ubuntu turn off the screens completely. Then I confirmed by trying to wake up the screen again, which I couldn’t.

After this I unplugged the screens again and put them back in. I then got to the login screen on the secondary screen, although it had reverted to default settings with the default background etc. When I logged in both the screens started flashing on and off until they eventually died. Had to restart the machine to get it working again. I have attached the syslog of this time period.
log.txt (235 KB)

I would like to add that I have tested with the 387.12 version of the drivers now as well, with the same result.

The AOC seems to behave fine, but the ASUS gets completely lost after a while and the kernel is always complaining about failed hdmi audio transfers. Gnome has its problems when the primary display gets lost, so what happens when you use the AOC as primary? Also, what happens when you connect the AOC to HDMI and the ASUS to DP via adapter?

Right, so I switched the ASUS screen to the DP-adapter and the AOC to the HDMI one. Computer/Xorg seemingly froze and I had to CTRL+ALT+F1 to get into a new session and grab the logs (attached).

Interesting now is that when I restarted the issue has vanished. I cannot reproduce the problem again with the current settings.

If I should test anything else and attach more logs I am more than willing to do that if it helps getting to the bottom of this and potentially produce a patch.

Note: I have not currently tried to switch the AOC to primary to see if that makes any difference.

Note 2: I would like to point out the similarities here https://devtalk.nvidia.com/default/topic/1025477/linux/x-org-crashes-on-ubuntu-17-10-with-driver-nvidia-384-after-upgrade/2
nvidia-bug-report.log.gz (258 KB)
log.txt (86.4 KB)

The thread you mentioned is about the symptom. Gnome gets into trouble when the primary monitor gets lost. The Gnome people said they fixed it, but obviously it’s still not really working.
The cause is that the ASUS gets lost. And you’re still getting XIDs and transfer errors but now on the DisplayPort. Means, it’s not driver related but hardware. I’d say that either the HDMI cable is flaky if you didn’t change it or the ASUS is announcing its sooner or later death.

I replaced the cable with new ones (that I had laying around), and it made no difference.
When having the Asus in the HDMI slot and the AOC in the DP-adapter I got the same issue as before where everything stays black and the screens do not wake up again.

Having the Asus in the DP-adapter and the AOC in the HDMI-slot works fine (with any cable).
Hopefully you are wrong about the Asus dying :D.

Hopefully this keeps working but if you should run into trouble again, maybe check if the DVI connector on the ASUS still works.

Would like to make an update to this thread since I ran into some problems today with the above mentioned “working” solution. I was watching a series using VLC, and when I wanted to jump forward into the episode the machine just froze.

Had to login via ssh from another machine, and ´tail -f /var/log/syslog´ revealed that it was continuously spamming the following (before seen) text.

Nov  5 16:51:48 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:51:49 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:51:50 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:51:50 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:51:50 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock

Tried to unplug the AOC screen from the HDMI port, which yielded the following result (still couldn’t retrieve my session). Also spamming the log for the record. Disconnecting the Asus screen didn’t change anything.

Nov  5 16:52:04 Teresa kernel: [197261.016951] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: connected
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:52:04 Teresa kernel: [197261.022255] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: connected
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:52:04 Teresa kernel: [197261.027490] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: connected
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:52:04 Teresa kernel: [197261.032722] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: connected
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:52:04 Teresa kernel: [197261.038022] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: connected
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: Internal TMDS
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): DFP-1: 165.0 MHz maximum pixel clock
Nov  5 16:52:04 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:52:04 Teresa kernel: [197261.043308] nvidia-modeset: WARNING: GPU:0: Unable to read EDID for display device AOC 2476WM (HDMI-0)

Connected the screens again and then it just continued like this until I rebooted the machine.

Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): connected
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): Internal TMDS
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0): AOC 2476WM (DFP-1): 600.0 MHz maximum pixel clock
Nov  5 16:53:17 Teresa /usr/lib/gdm3/gdm-x-session[1088]: (--) NVIDIA(GPU-0):

Is this still the same problem as before or is this a new development?
I haven’t tested the DVI port yet of the Asus screen, but I will dig out a cable and do that. But is the conclusion still that this is the fault of the Asus screen?

I would like to add that I can reproduce this issue by starting any video in VLC and click on the video timeline to fast forward, or simply double click the screen a few times to switch between full screen and windowed mode of VLC. This issue has probably been there the whole time, just that I haven’t watched anything with VLC for a while.

The problem is that the ASUS gets lost again, Gnome freaks out. Though the trigger might be different:
https://devtalk.nvidia.com/default/topic/1024285/linux/-vdpau-bug-certain-h-264-videos-cause-hardware-errors-nvrm-xid-pci-0000-01-00-68-ccmds/
Maybe try to set the output of vlc to something different than vdpau and see if you can still reproduce it.