945GM(E) screen rotation and slow GL.

[Rob Kramer]

Hi,

I have an embedded board with 945GM chipset (1.8GHz Celeron M) connected via
DVI to a 1920x1200 screen. I'm trying to benchmark GL performance a bit
with glxgears, which should be good enough to give a rough estimate of the
device's capabilities. (Is there a better generic GL benchmark tool?)

When testing screen rotation to portrait mode, the glxgears framerate drops
from 51 fps (not too great to start with) to 1 fps. 

I remember in the past there were always dire performance warnings regarding
XAA and rotation; impact of shadow FBs and all that. Is that still a valid
concern for a modern setup, i.e. is GL expected to be sluggish/unusable in
rotated mode? Should I not use the 'rotate' feature at all, but rotate GL
geometries/textures myself, in my application? (that would be painful, I
guess).

Using kernel 2.6.28.3. Xorg, drm, mesa are from Fedora rawhide. The intel
driver is git HEAD. For the driver, it doesn't seem to make a difference
whether I specify UXA or not.

Cheers,

    Rob