[Dri-devel] Re: Join forces towards DRI support for Savage4, Twister, Prosavage?

[Felix <fx...@gm...>]

On Mon, 22 Dec 2003 11:59:34 -0800
"Tim Roberts" <ti...@pr...> wrote:

> On Sun, 21 Dec 2003 16:35:01 +0100, Felix K_hling  wrote:
> >
> >as mentioned earlier on sav...@pr... I'm working on the savage S3
> >code drop, specifically on the 3D driver. A few days ago I managed to
> >get a working 3D driver ported to Mesa 4. It is now in DRI CVS on the
> >savage-2-0-0-branch. However, many users (including myself) are
> >experiencing more or less serious problems with the 2D driver from the
> >code drop. We have to use it for now as it is the only driver we have
> >that is DRI aware. It also has some nice features that would be worth
> >integrating into a reliable 2D driver, like interpolated scaling of
> >video overlays or hardware motion compensation.
> >
> >I have no experience with XFree86 2D drivers and not much useful
> >documentation of the Savage hardware. I was hoping that we could join
> >forces towards a Savage 2D and 3D driver combination for future XFree86
> >releases. Therefore I'm writing to you as the maintainer of the Savage
> >2D driver now.
> 
> Please allow me to emit a heavy sigh.  <sigh depth="heavy"/>
> 
> I want to help.  I do.  I feel a serious sense of ownership about the
> XFree86 Savage driver; it has brought me as close to "fame" as I am likely
> to experience in my lifetime.  However, it is unlikely that I will be able
> to spend more than a few hours on it for the next few months.

I understand. I'm also going to have less time after christmas for the
savage driver than I spent the last couple of weeks. So I guess
everybody should prepare for slow progress. But I do have some spare
time between christmas and new year. I was planning to start messing
with the 3D and kernel components, but maybe I'm going to play with the
2D driver instead. Unless, of course, someone else steps forward.

> 
> The 2D driver VIA submitted was forked from my code about 2 1/2 years ago,
> when they terminated my contract.  I know it does not include some of the
> fixes I have made since then, but someone who is competent with a 3-way
> diff tool should be able to merge those in.

Ok. It would be helpful to get as close to the version where the drivers
were forked initially. Can you recommend one of your code drops or a
specific date in XFree86 CVS?

> 
> Can you enumerate the problems people are seeing?  If the problems are
> familiar to me, perhaps I can offer valuable assistance without a huge
> time commitment.  I _do_ want to see this driver succeed.

These are the most annoying problems I can remember from the top of my
head:

- Savage 4 shows corruption with acceleration enabled. If tiling is
disabled then 2D works ok but 3D is garbled instead. ProSavage doesn't
have this problem. 2D works with or without tiling, but I guess tiling
is needed for 3D here too.

- Parts of the screen at top and bottom are black in some modes.
1024x768 is ok. 800x600 too, for me, but another user reported that a
few lines were missing. With 640x480 it's most noticable. Anther user
reported a similar problem at 1280x1024. There may also be a difference
depending on whether you start the Xserver with 640x480 or switch to
that mode from a higher resolution.

- Lockups when DRI is enabled when switching VTs or when moving 3D
windows. There are calls to a ScreenToScreen copy function in
savage_dri.c which I disabled. Now it doesn't lock up when moving 3D
windows anymore. I also managed to lock up the chip with quake2, but
that may be a pure 3D issue.

Any help you can offer will be welcome, code or advice.

> --
> - Tim Roberts, ti...@pr...
>   Providenza & Boekelheide, Inc.
> 

Regards,
  Felix

P.S.: I have two small problems with your latest driver too. Don't know
if this is the right place and time to mention them.

------------    __\|/__    ___     ___       -------------------------
 Felix       ___\_e -_/___/ __\___/ __\_____   You can do anything,
   Kühling  (_____\Ä/____/ /_____/ /________)  just not everything
 fx...@gm...       \___/   \___/   U        at the same time.