The issue reproduced again, some time after I have unplugged the notebook from the docking station, then connected, and finally disconnected the D-SUB vga connector. I should have the newest bios installed:
$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date L77 Ver. 01.33 07/20/2015 The relevant dmesg messages: Notebook got disconnected from the docking station: [21032.211507] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [21032.224120] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [21032.226734] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [21032.226997] acpi PNP0501:00: Still not present [21032.227373] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment Then, after some time and after DSUB connect and disconnect: [22058.949238] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A [22058.949264] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun [22058.964980] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe B [22058.964997] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun [24580.055198] [drm:intel_dp_start_link_train [i915]] *ERROR* failed to enable link training [24580.060997] [drm:intel_dp_complete_link_train [i915]] *ERROR* failed to start channel equalization ** Changed in: xorg (Ubuntu) Status: Incomplete => New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1509355 Title: xorg crashes because of intel gpu driver To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1509355/+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