[Savage40] New Savage DRM preview

Felix Kühling fxkuehl at gmx.de
Wed Dec 29 09:29:42 PST 2004


Hi all,

After a few coding night shifts over the holidays the development of the
new Savage DRM driver finally reached a stage where I am pretty
confident that no more binary-incompatible changes to the interfaces
between DDX, DRM and the 3D driver will be needed. I uploaded my work in
the form of three patches to http://freedesktop.org/~fxkuehl/savage. I
am going to get this committed to the various CVS repositories ASAP so
that all further work can happen under version control again. Anybody
who is comfortable with compiling X.org, DRM and Mesa from source should
apply these patches and test them. It's worth it! :-) (see the Feature
summary below)

IMPORTANT: If you get lockups with these patches try enabling
ShadowStatus in xorg.conf. This fixed lockups related to vertex DMA on
all hardware I tested. In fact, I would be surprised if anyone got away
without lockups without ShadowStatus. Therefore a future version of the
driver may refused to enable DRI if ShadowStatus is disabled.

Feature summary:
      * Version numbers of DRM and DDX were bumped to 2.0.0 in order to
        reflect the binary incompatibility to previous versions.
      * Secure DRM and DDX drivers that do not allow unprivileged 3D
        applications direct access to the hardware.
      * Should be stable on a larger variety of hardware by using shadow
        status in the DRM if it is enabled in xorg.conf.
      * Better performance by using vertex DMA when possible.

Because of experimentation with the binary interfaces I kept my work out
of CVS for quite some time. I tried to limit the amount of changes to
what was absolutely necessary in order to get things working properly.
There are some features which will be implemented in the near future.
Some of them are already sketched in the patches but not implemented
yet. See the TODO list for details.

TODO:
      * Apply clipping rectangles to 3D drawing commands.
      * Support for PCI cards.
      * Command DMA on Savage4-based hardware for better performance.
      * Use DMA for texture uploads.
      * Implement a fast path with less overhead that makes more
        efficient use of available hardware primitives.

Best regards,
  Felix Kühling

-- 
| Felix Kühling <fxkuehl at gmx.de>                     http://fxk.de.vu |
| PGP Fingerprint: 6A3C 9566 5B30 DDED 73C3  B152 151C 5CC1 D888 E595 |

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