Intel GPU error, PCH transcoder A FIFO underrun

[Alex G.S.]

List,

Every time I browse my 'journactl -b' logs I always see the following error:

[drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch
fifo underrun on pch transcoder A
[drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A
FIFO underrun

It also happens around times when I'm doing something graphically intensive
and often precedes lockups.  But these lockups are rare and do not happen
often.  The error message itself appears on nearly all of the Intel HD
graphics chips I've used which are both the Intel HD 4000 and Intel HD 4600.

I'm just curious as to any workarounds that could solve this in the
short-term.  Of all the bug reports I've read they always end with no
resolution or "version 4.0 of the Kernel will solve this", but I'm on
Kernel 4.1+ and it's still not solved yet.

Thank you for any information you can provide...

Regards,
Alex G.S.

[Evandro Giovanini]

On Sat, Aug 29, 2015 at 3:04 PM, Alex G.S.  wrote:
> List,
>
> Every time I browse my 'journactl -b' logs I always see the following
> error:
>
> [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch
> fifo underrun on pch transcoder A
> [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A
> FIFO underrun
>
> It also happens around times when I'm doing something graphically
> intensive and often precedes lockups.  But these lockups are rare and do
> not happen often.  The error message itself appears on nearly all of the
> Intel HD graphics chips I've used which are both the Intel HD 4000 and
> Intel HD 4600.
>
> I'm just curious as to any workarounds that could solve this in the
> short-term.  Of all the bug reports I've read they always end with no
> resolution or "version 4.0 of the Kernel will solve this", but I'm on
> Kernel 4.1+ and it's still not solved yet.
>
> Thank you for any information you can provide...

Downgrade from 4.1 to 4.0 to fix it.

Evandro

[Michael Catanzaro]

On Sat, 2015-08-29 at 16:23 -0300, Evandro Giovanini wrote:
> Downgrade from 4.1 to 4.0 to fix it.

FWIW, my laptop has had these same errors for as long as I can
remember.