[Nouveau] nouveau interrupts firewire ISO streaming

[Maarten Maathuis]

On Thu, Feb 4, 2010 at 1:38 PM, Adrian Knoth <adi at drcomp.erfurt.thur.de> wrote:
> On Thu, Feb 04, 2010 at 12:19:14PM +0100, Maarten Maathuis wrote:
>
> Hi!
>
>> >> > When the X pointer changes from arrow to the vertical text selection
>> >> > bar, firewire streaming is interrupted. Same with scrolling in firefox
>> >> > or hovering over a link, thus changing the pointer to "hand".
>
>> It's mostly cpu copying the cursor. Now that i think of it, we keep a
>> copy of the cursor inside the kernel, so no need to make the userspace
>> side vram too. As a quick test you could try changing VRAM to GART
>> here http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/tree/src/drmmode_display.c#n641.
>
> Changing to GART fixes the cursor issue. Hovering over a link now no
> longer stalls my audio streams.
>
> Is there something similar I could try to fix scrolling or even raising
> a window, thus changing the colour of the title bar? Both still
> interrupt audio.

Sounds like your situation is sensitive to accessing gpu memory
somehow, but this is just a guess. The cursor was a very special
isolated case, this is a more generic problem.

Change this to "if 1" to get some information of when cpu rendering
happens. http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/tree/src/nouveau_local.h#n33

You could also add some verbosity to
http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/tree/src/nouveau_exa.c#n291
and http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/tree/src/nouveau_exa.c#n302,
which would capture everything.

>
>> Assuming you don't have an agp system, otherwise you will still be
>
> PCIe.
>
>
> Cheerio
>
> --
> mail: adi at thur.de       http://adi.thur.de      PGP/GPG: key via keyserver
>