Score:1

External monitor stopped working (but all is ok on fresh install)

cn flag

I have a problem with my Lenovo Thinkpad T14s (AMD!) stopped recognizing an external display connected with usb-c (not thunderbolt). It had Ubuntu 20.04.2 installed when this happened, and I have since updated to 21.04 and 21.10 with no change. Interestingly the display works fine when I install a new, fresh 21.10 on a new partition, so hardware failure is ruled out (in the fresh install, both x11 and wayland works fine).

I have googled and tried many suggestions, including most suggestions here on AskUbuntu that I thought relevant, but nothing helps. Since it works on a fresh install, my idea is that there must be some config and/or packages that are different, but I need help to figure out what can be wrong!

es flag
Does the workaround from another [bug](https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-340/+bug/1946987) work in your case?
cn flag
@jarno Thanks, but it did not help
Score:0
cn flag

Posting this here for reference.

Somewhere along the way the amdgpu driver was blacklisted. I simply deleted the /etc/modprobe.d/blacklist-amdgpu.conf file, rebooted and everything works again.

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.