Re: System hung for a few minutes on rt kernel

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2017-07-30 19:37:41 [+0200], Jacek Konieczny wrote:
> Hi,
Hi,

> 
> Jul 30 19:12:22 lolek kernel: [drm:intel_pipe_update_end [i915]] *ERROR*
> Atomic update failure on pipe A (start=40468 end=40469) time 173 us, min
> 1073, max 1079, scanline start 1068, end 1081
> [...]
> Jul 30 19:18:46 lolek kernel: [drm:intel_pipe_update_end [i915]] *ERROR*
> Atomic update failure on pipe A (start=63501 end=63502) time 249 us, min
> 1073, max 1079, scanline start 1065, end 1081
> Jul 30 19:19:58 lolek kernel: [drm:intel_pipe_update_end [i915]] *ERROR*
> Atomic update failure on pipe A (start=67818 end=67819) time 100 us, min
> 1073, max 1079, scanline start 1072, end 1080
> Jul 30 19:21:33 lolek kernel: [drm:intel_pipe_update_end [i915]] *ERROR*
> Atomic update failure on pipe A (start=73522 end=73523) time 127 us, min
> 1073, max 1079, scanline start 1071, end 1080
> 
> System seems to be working correctly after the lockup.
> 
> Any ideas what is going on?

It is possible, that the task doing i915 hung for some reason and
blocked other tasks while doing so. I can't answer why. But it looks
like once i915 recovered, it released some locks and the remaining part
of the system continued to work.

One thing: You could if the number of your problems decrease if you
switch from CONFIG_NOHZ_FULL to CONFIG_HZ_PERIODIC.

> Jacek

Sebastian