Ubuntu
xserver-xorg-video-intel package

  1. Bug #1552040
  2. Comment #14

Comment 14 for bug 1552040

Revision history for this message
Sergey Menshikov (sergem) wrote : Re: Laptop sometimes doesn't detect external monitor

Ubuntu 17.10 Gnome/Xorg Lenovo 4th gen X1 20FBxxx Skylake i7 Intel built-in video
Kernel 4.13.0-32-generic #35-Ubuntu SMP

When connecting Thinkpad Dock with 2 Dell monitors, screen locks up (mouse is moving though) and is not responding. Monitors are not recognized. Unlocks 20 sec after disconnect. Happens every time after first connection following a reboot (first connection after reboot is OK)

dmesg shows a lot of:
drm:intel_wait_ddi_buf_idle [i915_bpo]] *ERROR* ...

Workaround:

sudo vi /usr/share/X11/xorg.conf.d/20-intel.conf

paste:

Section "Device"
 Identifier "Intel Graphics"
 Driver "intel"
 Option "DRI" "3"
EndSection

reboot
The issue does not return, unless the above file it removed.

Hat tip to https://wiki.archlinux.org/index.php/intel_graphics#Skylake_support