How to enable 3D acceleration with Sis Vga 771/671 on Ubuntu 12.04

Question

It's been a while since I configured a good resolution with my sis vga 771/671.

How can I enable the 3D acceleration with this video card?

Solution

This is a good question, but I'll explain (with my story) why it's not currently possible with this particular SiS hardware.

I have been trying to get hardware acceleration working on SiS chipsets, but have never succeeded; 2D acceleration and video acceleration seem to work well. In your xorg.0.log, you will probably have a similar error as this:

AIGLX: Screen 0 is not DRI2 capable
AIGLX: Screen 0 is not DRI capable

This means that DRI is disabled: DRI is known as Direct Rendering Infrastructure and is the rendering standard used on Linux based systems for 3D acceleration by such means as opengl. However, the open source driver does not support it and there are unfortunately no proprietary drivers for the SiS hardware: the source code and specifications have never been released.

Thomas Winischofer was the man who thankfully contributed the code so that SiS adapters can actually work in Linux based systems; his site is here and contains useful technical information and he particularly mentions here that

There is no DRI/OpenGL/3D support for the SiS 6326, 5597/5598, 530/620, 315, 550, 650, 651, 740, 330, 661, 741, 760, 761 including all model variations with letters in the model number.

Again, at the freedesktop site it is noted that there are no available DRI drivers for your model unfortunately. It is seen as a wishlist item rather than a bug at Launchpad because it won't be worked on by the Ubuntu developers, but it is up to those at the dri project and others. However it is very unlikely that a suitable driver will be produced because the source code has never been released by SiS.