@Tomasz Przybysz i915.enable_rc6=0 as a workaround doesn't seem to work. I have similar symptoms as Angelo Lisco. I leave laptop on overnight and sometimes in the morning it got frozen with same underrun error message in logs.
enable_rc6 is definitely set to 0: $ cat /sys/class/drm/card0/power/rc6_enable 0 And the bug is still there with kernel 4.15.10 =( just a heads up -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1550779 Title: [i915]] *ERROR* CPU pipe A FIFO underrun - Xorg glitches To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1550779/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs