[Bug 103029] New: Reoccuring CPU pipe [A|B] FIFO underrun followed by corrupt external monitor

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=103029

            Bug ID: 103029
           Summary: Reoccuring CPU pipe [A|B] FIFO underrun followed by
                    corrupt external monitor
           Product: DRI
           Version: unspecified
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: martin.weinberg at comcast.net
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

Created attachment 134548
  --> https://bugs.freedesktop.org/attachment.cgi?id=134548&action=edit
Output of lspci

Since Kernel 4.13, I've been experiencing problems with my Lenovo T440s while
on the Ultradock using HDMI.  No problems on earlier kernel.  This has occured
on 4.13.0 through 4.13.3 (*current*).

A mostly successful work around is to suspend and resume off the dock.

T440s is Haswell; output of lspci attached. I'm using Ubuntu 17.04, uname -a
is:

Linux magpie 4.13.3-041303-generic #201709200606 SMP Wed Sep 20 10:12:46 UTC
2017 x86_64 x86_64 x86_64 GNU/Linux


Specifically, the log contains entries like: *ERROR* fifo underrun on pipe B

Some fraction of the time, but not every time, this occurs, the external screen
becomes corrupted.  It acts as if it's lost sync.

There are no additional kernel messages.  To help, I rebooted with
drm.debug=0xe to capture an "event".  I'm attaching part of the log with drm
messages below.

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