[Intel-gfx] FBC underruns on GMA4500?

[Alexey Fisher]

On Mo, 2010-08-09 at 09:36 -0700, Jesse Barnes wrote:
> On Sat, 07 Aug 2010 11:46:19 +0200
> Alexey Fisher <bug-track at fisher-privat.net> wrote:
> 
> > Hallo all,
> > 
> > i have some times on my primer desktop with Intel DG45ID board some sort
> > of flickering, it schort (1 second) and only half of the display. Same
> > sort of flickering i had with Bug 24314 - [945GME FBC] underruns
> > followed by freeze after resume with FBC enabled. The difference is - it
> > will not freeze.
> > 
> > If i understand it correctly , it is not normal. But i can't report it,
> > there is no messages in dmesg or xorg.log
> 
> Sounds like potential FIFO underruns, maybe your memory configuration
> doesn't match the latency we expect in intel_display.c.  You could try
> increasing the latency constant in that file to see if it makes the
> flicker go away.

Can you please point me what file to change? And haw can i check what
latency is used?

> If that helps it's just another example of why we need better latency
> detection in the driver; unfortunately we don't know how to do that
> yet...

Please take a look to this bug:
https://bugs.freedesktop.org/show_bug.cgi?id=29454
may be FIFO underrun and hangs have same source.

Regards,
	Alexey