[Bug 116571] New: Wild screen flickering and errors drm:intel_set_cpu_fifo_underrun_reporting and drm:intel_cpu_fifo_underrun_irq_handler in dmesg

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=116571

            Bug ID: 116571
           Summary: Wild screen flickering and errors
                    drm:intel_set_cpu_fifo_underrun_reporting and
                    drm:intel_cpu_fifo_underrun_irq_handler in dmesg
           Product: Drivers
           Version: 2.5
    Kernel Version: 4.5
          Hardware: All
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Video(DRI - Intel)
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: hanno at hboeck.de
                CC: intel-gfx-bugs at lists.freedesktop.org
        Regression: No

Created attachment 213141
  --> https://bugzilla.kernel.org/attachment.cgi?id=213141&action=edit
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.

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