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<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - [IVB] at boot all displays cycled on/off over and over *ERROR* CPU pipe B FIFO underrun"
href="https://bugs.freedesktop.org/show_bug.cgi?id=90307#c2">Comment # 2</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - [IVB] at boot all displays cycled on/off over and over *ERROR* CPU pipe B FIFO underrun"
href="https://bugs.freedesktop.org/show_bug.cgi?id=90307">bug 90307</a>
from <span class="vcard"><a class="email" href="mailto:chris.bainbridge@gmail.com" title="Chris Bainbridge <chris.bainbridge@gmail.com>"> <span class="fn">Chris Bainbridge</span></a>
</span></b>
<pre>The problem is that these bugs are rare and difficult to reproduce. I just had
a similar/same error that turned off only one display, but it occurred after 22
days of uptime:
[1889327.745544] [drm:intel_set_cpu_fifo_underrun_reporting] *ERROR* uncleared
fifo underrun on pipe B
[1889327.745556] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe B
FIFO underrun
[1889327.745583] [drm:intel_set_pch_fifo_underrun_reporting] *ERROR* uncleared
pch fifo underrun on pch transcoder B
[1889327.745585] [drm:intel_pch_fifo_underrun_irq_handler] *ERROR* PCH
transcoder B FIFO underrun
It could be recovered by `xrandr --off` then `xrandr --auto`. Maybe the log
gives some hints, but a bug that only appears once in 22 days would take a long
time to track down...</pre>
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