r300 vb path

[Ben S. <dar...@ii...>]

Hello,

I've attached a patch with a port of the r200 vertex buffer code for the 
r300 driver.
The performance of the vertex buffer codepath is now roughly the same as the
immediate path, and tuxracer now seems to be rendered almost correctly.

Vladimir, I haven't found a way that I can directly call the 
r200/radeon's discard buffer
command from r300_dri, so this patch still includes the drm additions.  
Perhaps someone
could help me out with this one?

Could the people testing r300_dri test this if they have the time?  And 
Vladimir, can you
let me know if you want me to commit this, or if it needs more work.

Thanks,
Ben Skeggs.