No signal for the second monitor

Graphics / Linux Linux
1

Hello,

My second monitor is not detected on Ubuntu 21.10 although everything was okay 2-3 days ago.

  • I have tried to reinstall “nvidia-driver-470” as recommended in the output of ubuntu-drivers devices 
sudo prime-select nvidia
sudo rm /etc/modprobe.d/blacklist-nvidia.conf /lib/modprobe.d/blacklist-nvidia.conf
sudo update-initramfs -u

  • I’ve also tried removing blacklist files(there were none.)

  • I also modified /lib/modprobe.d/nvidia-kms.conf file and changed 1 to 0.

Here is my bug report.
nvidia-bug-report.log.gz (371.4 KB)

Any advice on how to resolve that issue? Thanks in advance.

2

Your nvidia gpu is added as “3D device” which might point to it having no outputs at all. Your intel igpu also reports no other outputs than the internal display. I suspect a kernel bug in the i915 driver, can you return to a previous kernel in grub menu?

3

After you said it might be related to a kernel bug, I checked which kernel has been used last time the external monitor worked fine, it was my current kernel “linux-image-5.13.0-21-generic”. Anyhow, I switched back to “linux-image-5.13.0-20-generic” and it worked just fine. To try again, I switched back to a newer kernel, and it is working properly mysteriously. :) Thank you for your interest. You’re a life-saver.