Thanks for looking so quickly. I'm almost certain the problem will go away without the nvidia driver because the nouveau driver didn't recognise the hardware when I booted off the USB installer, so reverse prime won't work and there will be no external monitor, which is a completely new problem.
I was logged into a clean profile with no non-standard gnome-shell extensions running, and 'top' showed Xorg (40%) and irq/93-nvidia (1%) and nvidia-modeset/ (0.3%) as the top three CPU hogs, so it's unlikely to be extensions causing it. FYI, when I checked the journal log for those nv_drm_master_set errors right now, I can see a bunch at 11:47 and another bunch at 11:54, but nothing since (it's now 12:43). But the CPU usage is still high. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1944667 Title: High CPU usage in Xorg with NVIDIA reverse prime external monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-470/+bug/1944667/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
