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Arno
Asked: 2020-09-03 22:28:15 +0800 CST

Ubuntu 20.04 : continious screen flicker after return from supend ( *ERROR* CPU pipe A FIFO underrun )

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After return from suspend the screen of my laptop flickers. You can't continue work with that. In kernel log you see :

[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

So I played with display settings. Changing the refresh rate doesn't help, but lower the resolution (from 1920x1080). So in any lower resolution I don't have a problem. But of course I have to loose a lot of pixels when using a default resolution. So I decided to add my own 1912x1080. For some strange reason this is enough to avoid flickering.

So I added this lines to my ~./profile:

xrandr --newmode "1912x1080_60.00"  171.25  1912 2032 2232 2552  1080 1083 1093 1120 -hsync +vsync
xrandr --addmode eDP-1 "1912x1080_60.00"

and select this resolution. The issue is gone but I am really wondering what is root cause of this?

My system is a Skylake core-m5-6Y54 system, running Ubuntu Mate 20.04.

display-resolution suspend flicker intel-graphics 20.04

1 Answers

  1. I was able to prevent this from happening by disabling C-States in my laptop's firmware configuration ("BIOS"). For reference, it's a Dell Latitude 5490.

    Source of the solution, click here. I had same problem.

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