I've been struggling with this all day. My solution (on Ubuntu 20.04) is to downgrade to nvidia driver 435. Change gdm3 to lightdm.
In that exact order apt install nvidia-driver-435 apt install --reinstall lightdm ubuntu-desktop The bug is in driver 440. Also confirmed this in Arch Linux as well. gdm still doesn't allow HDMI output even in 435. ** Attachment added: "Screenshot from 2020-06-01 20-16-00.png" https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-440/+bug/1871721/+attachment/5379464/+files/Screenshot%20from%202020-06-01%2020-16-00.png -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1871721 Title: Second Monitor on HDMI blank screen with Nvidia & Ubuntu 20.04? (ASUS Laptop) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kernel-package/+bug/1871721/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
