[Intel-gfx] [PATCH] sna: avoid negative timeouts

[Felipe Contreras]

On Thu, Oct 3, 2013 at 2:36 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Thu, Oct 03, 2013 at 01:29:29AM -0500, Felipe Contreras wrote:
>> It's nice to avoid X server crashes (by not passing negative values to
>> select(3)).
>>
>> For more information:
>> http://article.gmane.org/gmane.comp.freedesktop.xorg.devel/37388
>>
>> Signed-off-by: Felipe Contreras <felipe.contreras at gmail.com>
>
> Thanks for the patch, I pushed a slightly different version to consume
> the expired flush timeout immediately.
>
> However, in order for this to happen something within the BlockHandler
> must have run for at least 4ms. Which is itself very worrying - the two
> candidates are the throttle or lock contention. (The throttle is also
> prone to being influenced by a third party.) Such stalls are likely to
> be noticeable as jitter or judder, so if you can spot their source
> hopefully we can tackle the root cause.

What exactly do you mean by third party? I wouldn't notice if there
was jitter because it's a loading screen, and there's absolutely no
updates on the screen; it's static.

Do you mean you would like me to add debugging in
sna_accel_block_handler() to figure exactly which block is taking too
long to complete?

-- 
Felipe Contreras