On Mit, 2002-02-20 at 18:11, Gustavo Alberto Homem wrote: 
> > 
> > I can only guess why 4.0.3 worked better than 4.1.0; I guess it's
> > because the r128 driver in 4.0.3 didn't properly support 420 video (or
> > was it 422? I forget :) yet.
> 
> I don't know exactly what are those 420 and 422 ? Image formats ?

Yes.

> How does that justify the fact that mpeg2 overlay performance degraded ?

I was going to suggest that the better performance might have been at the
cost of image quality, but I'm even less sure now...

> What I complain about (with XFree 4.1 and XFree 4.2 DRI disabled) is a
> very high cpu load when using XV output, which causes frame dropping.
> With Xshm output I get no frame drops and Xv was supposed to provide better
> performance, so I have to conclude that Xv output is broke in either 4.1
> and 4.2 , in the latter case it is broke in 2 different ways (but only for
> mpeg).

Other reports seem to back your suspicion that something is badly broken;
unfortunately, I have no idea what. Someone will have to track it down.


> > > 2 - The KDM login screen is completely messed (widgets are garbaged, not
> > > drawn properly)
> > 
> > I have fixed this in DRI CVS and submitted the fix to XFree86.
> > 
> > Both 1) and 2) are due to the fact that the r128 driver does 2D
> > acceleration differently with DRI enabled now. I'm sure you've also
> > noticed the better 2D performance. :)
> 
> I read that the 2d acceleration mode had to be changed because it was
> incompatible with the use of bttv, but why have two diferent
> implmentations ?

There are two ways to program the chip which don't mix well. There's
apparently a way to simulate one using the other though, which could indeed
be used to unify the code.

> What I noticed was that with DRI enabled Xv ouput was smooth again before
> crashing (colors were wrong though), but that was the usual situation with
> 4.03 regardless of DRI beeing enabled or disabled.

It was smooth because the DRM was used to transfer the image data using DMA.


> > > What is exactly the relation of Xvideo and dri ?
> > 
> > They are conceptually independent, however as of 4.2.0, the r128 driver
> > tries to take advantage of the DRM to accelerate Xv image transfer.
> > Unfortunately, this doesn't work well with some chips, and there are
> > also problems coordinating this with the new 2D acceleration yet.
> 
> hmm, I had a very quick look at dri.sf.net info, and I think I read drm
> was 3d only and that 2d data would allways go to the X server (they have a
> picture :) ). Did this change ? Is drm going to be used for 2d in the
> future ?

The DRM is a generic resource manager. It was traditionally only used by the
DRI, but that seems to be changing.


-- 
Earthling Michel D�nzer (MrCooper)/ Debian GNU/Linux (powerpc) developer
XFree86 and DRI project member   /  CS student, Free Software enthusiast
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