Created attachment 213141 [details]
dmesg output when bug appears

Starting with kernel 4.5 I occasionally get a wild screen flickering. In lack of a better description I have uploaded a video recording of the phenomena:
https://www.youtube.com/watch?v=VYxRvFsS-nY
The flickering seems to be triggered by touchpad movements (if I don't do anything the flickering becomes less and sometimes the screen is just black, if I move the mouse cursor with the touchpad the flickering becomes wilder again).

When this happens dmesg shows these errors:
[   15.649635] [drm:intel_set_cpu_fifo_underrun_reporting] *ERROR* uncleared fifo underrun on pipe A
[   15.649641] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe A FIFO underrun

The system is a Thinkpad X1 Carbon 2014 edition (20A7), the GPU is listed as "Haswell-ULT Integrated Graphics Controller (rev 0b)" by lspci. I'll attach full dmesg, kernel config and lspci output.
If there's any other info you need to analyze this please ask.

I have tried to git bisect this bug, but it's not easy, because there is no reliable reproducer. It appears after a while, but not in a predictable pattern. Sometimes it simply appears when I open a browser, sometimes without any apparent reason.

Falling back to kernel 4.4 (using 4.4.1) this does not happen, so the change must have been introduced between 4.4 and 4.5.