This does not appear to be exclusive to the nouveau or xorg. I've been able to reproduce it at the console by plugging in display port without X11 running.
I open htop, everything looks fine. Then I plug in the display port cable and the CPU immediately shoots up to 100%. I've also loaded the intel driver (rebooting into macOS, selecting integrated driver and confirming it is running with vga_switcheroo once i reboot back into linux), and i get the exact same behavior. Note, booting with the displayport cable attached will cause the system to hang during initialization, I guess because the kworker takes 100% of the CPU. I've also had this happen with the proprietary nvidia driver loaded. This doesn't seem to have anything to do with the graphics driver, but rather the kernel itself is having a hard time with the thunderbolt port managing the display port connection. Oddly enough, this issue doesn't happen 100% of the time for me. I've had days where it didn't happen at all, and days where it is non stop. I'm running out of ideas on debugging this one, other than that the problem is almost certainly in the kernel itself, and is probably related to sketchy thunderbolt support since this never happens with just normal HDMI output. -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-nouveau in Ubuntu. https://bugs.launchpad.net/bugs/1248256 Title: [MacBookPro10,1] Plugging in displayport monitor causes kworker to take 100% CPU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/1248256/+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
