Ubuntu
linux package

  1. Bug #1550779
  2. Comment #76

Comment 76 for bug 1550779

Revision history for this message
Yury Shefer (shefys) wrote : Re: [i915]] *ERROR* CPU pipe A FIFO underrun - Xorg glitches

I see the problem on my Thinkpad T450 when I connect external display on 16.04 LTS with Linux kernel 4.13.0-26-generic:

dmesg -T | grep i915
[Thu Jan 18 15:24:30 2018] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[Thu Jan 18 15:24:30 2018] [drm] Initialized i915 1.6.0 20170619 for 0000:00:02.0 on minor 0
[Thu Jan 18 15:24:31 2018] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[Thu Jan 18 15:24:37 2018] snd_hda_intel 0000:00:03.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[Thu Jan 18 16:05:48 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:07:26 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:20 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:22 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:29:56 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:31:29 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:31:37 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[Thu Jan 18 16:35:19 2018] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

Not sure what's the workaround. I don't see the problem when I use laptop's display.