Intel GMA 900 & XVideo Accelleration (i810 drivers)

[galenz at zinkconsulting.com]

On Sep 10, 2006, at 12:08 PM, Andrew Barr wrote:

> On Sun, 2006-09-10 at 10:29 -0700, galenz at zinkconsulting.com wrote:
>> Hello,
>>
>> I have a machine with the Intel GMA 900 graphics chipset. It works
>> beautifully under Linux... except I'm still struggling to get video
>> playback acceleration working with VLC.
>>
>> I have three sample clips, played in VLC 0.8.4a under Fedora Core 5.
>> One DVD-resolution and bitrate, and two HD bitrate clips, one 720p
>> and another 1080i. With X11 Video output, the sample clips works
>> perfectly, but are CPU intensive and/or choppy.
>>
>> I want to use XVideo output, because my chipset supports XVideo and
>> Xvideo motion compensation. I found the DVD resolution clip worked
>> fine out of the box. But the HD clips didn't - VLC would segfault. As
>> far as I can tell, VLC is fairly well coded, so things should
>> generally work.
>
> Are you sure it is segfaulting or is it encountering an X server  
> error?
> If the latter is the case, you should set the LinearAlloc parameter  
> for
> the i810 driver. See 'man i810' for the right values for HD playback.

man i810 does not mention LinearAlloc.

Could somebody explain to me what the LinearAlloc and CacheLines are?  
I mean, I have some idea... but what are the units?

I enabled LinearAlloc to 32768 - higher than the minimum values most  
people on Google suggest for HD.

When I attempt to play the 1080i file using XVideo, continues to VLC  
segfault. From /var/log/messages:
vlc[2871]: segfault at 00002aaab99d5000 rip 00002aaab869d8e3 rsp  
000000045006fc8 error 6

Note that the exact numbers vary a little bit each time. But it's  
always error 6. (Except one time out of dozens which is error 7.... I  
can only guess that was a fluke.)

Other than that, the only VLC-related errors in that log are like this:
audit(1157882914.686:23): avc: granted {execmem} for pid=2930  
comm="vlc" scontext=user_u:system_r:unconfined_t:s0  
tcontext=user=user_u:system_r:unconfined_t:s0 tclass=process

Occasionally, a similar line will occur that is like that but reads  
{execstack} instead of {execmem}.

I've also tested MPlayer with the XVideo extension. The results are  
very similar: the DVD and 720p resolution clips works, but the 1080i  
one fails. MPlayer reports:
"FATAL: Could not initialize video filters (-vf) or video output (-vo)."

-Galen