I have a Dell XPS 15 and connect over USB C to a display port hub to a HDMI external monitor.
Sometime in the past few months I ran into this issue. When I would lock my screen (xflock4) or go into standby the computer would lock up on resume and I had plenty of the following in the logs. drm:intel_wait_ddi_buf_idle [i915_bpo]] *ERROR* Timeout waiting for DDI BUF B idle bit It was fine on startup, as long as it didn't lock the screen. I had been running kernel 4.4.0 on Xubuntu 16.04 I upgraded to kernel to 4.10.0 and my issue is now fixed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1552040 Title: Laptop sometimes doesn't detect external monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1552040/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
