[compiz] radeon or radeonhd or xf86-video-ati ( was Re: Will radeon or radeonhd work with compiz?)

[Wil Reichert]

On Tue, May 12, 2009 at 11:25 PM, David C. Rankin, J.D.,P.E.
<drankinatty at suddenlinkmail.com> wrote:
> On Saturday 09 May 2009 10:49:50 you wrote:
> <snip>
>>
>> Cool.  I suspect this is the just the compiz default, why I have no idea.
>>
>> The fglrx driver is typically faster than either open source drivers
>> in 3D, but I'll take the performance hit over a binary blob any day.
>> I noticed in your logs you are using XAA, you can see if switching to
>> EXA makes any of the issues go away.  Alternately, theres the
>> xf86-video-ati driver you can try as well.  It shares a lot of code
>> with radeonhd but sometimes it works better.
>>
>> Wil
>
> Wil,
>
>        You got me here. What do you mean EXA v. XAA? How do I change to test? I have
> tested both the radeon and radeonh drivers and can't tell much of a
> difference, if any. You also suggest trying the xf86-video-ati. Is it
> supposedly faster than the radeon and radeonhd drivers? I'll poke around some
> more, but if you have a few extra bits of info on it, I'd appreciate it.
> Thanks.

XAA & EXA are the 2 different acceleration methods for most X drivers.
 Intel additionally has UXA, but its based on EXA.    I don't know
about the radeonhd driver, but the ati one defaults to XAA even tho
EXA generally provdes better performance these days (the commit has
been made to change the default to EXA in git, its just not released
yet).  Just add a line like

Option "AccelMethod" "XAA"
or
Option "AccelMethod" "EXA"

to the Device section in your xorg.conf file to change between them.
/var/log/Xorg.0.log will confirm what is getting used.

Wil