[Openchrome-users] Freezes with K8M890

[Thomas Steffen]

Well, I nailed it - although using oprofile is not as easy as it could
be. As expected the driver got stuck in the kernel, or more precisely
in via_dma.c:via_wait_idle(). Shortening the timeout makes it so quick
that it is no longer a noticeable delay. I used:

       int count = 500000;

down from 10000000.

Ok, so it works, but why does it go wrong in the first place? I don't
know. Well, I have a guess, but for some reason I cannot figure out my
trace statements (DRM_ERROR) have no effect - so that remains
difficult to analyse. I still hope that I can get a bit further there.

And does it have any negative influence? I have not noticed any.

Regards,
Thomas

On Thu, Feb 5, 2009 at 11:02 PM, Thomas Steffen
<steffen.listaccount at gmail.com> wrote:
> Hi all
>
> I have a very specific problem with the openchrome driver: the system
> freezes up for about 4 seconds during certain graphics operations, and
> I would like some help on investigating it.
>
> The board is based on the K8M890 chipset, so it should have a Chrome9
> HC (?) graphics card (and an Athlon 64 3200+). I use the AMD64 edition
> of mythbuntu 8.10. I have attached my xorg.conf and Xorg.0.log below.
>
> I have tried basically every option of the openchrome driver, with no
> success. I can either disable DRI (for example by using backingstore),
> and then the freezes go away (but the graphics get very slow), or I
> have these freezes. I tried EXA, all the XaaNo* options, NoXVDMA,
> NoAGPFor2D, DisableVQ, DisableIRQ, EnableAGPDMA, with no success.
>
> The freezes occur in very reproducible situation: when mythtv draws
> the background image, then during theme rescaling, and when XV is
> started or stopped. I guess it could be related to the Qt toolkit?
> During the freeze, the computer does nothing - no response to the
> network, and no log activity. After 4 to 5 seconds it becomes
> responsive again, and continues without an other issues. This happens
> a few times during the start of mythtv, so it is annoying, but not
> completely fatal.
>
> Now how could I investigate the reason for the freezes? It seems the
> openchrome driver does not offer a lot of debugging or logging, so I
> could add more tracing statements. But the better approach would
> probably to use a profiler - the only question is whether it would be
> able to profile during the freezes. Any recommendations?
>
> I also tried alternative drivers. The VIA driver does not work under
> AMD64. The openchrome driver under i386 crashed my system, and I could
> not get the VIA driver to work (some path issue, I think). I tried
> more different kernels (2.6.24 - 2.4.29), and different X versions
> (from Ubuntu 8.04 to the development version), but the problem is very
> persistent. The system I am using now is kernel 2.6.27-11.27, X server
> 1.5.2-2ubuntu3, openchrome 0.2.903-0ubuntu3.
>
> Regards,
> Thomas