i810 problems and questions

[Jan Rychter]

I've decided to give the new xorg release (7.1) a try in the hope that
the 855GM in my tablet pc will now be fully supported. And, lo and
behold, we're almost there!

Things I've found so far:

1. I can get acceleration in normal orientation, which is good.

2. It seems I can't get acceleration when rotating the screen
   CW. Windows move around sluggishly, xterms scroll slower, web pages
   scroll in a jerky manner. This is how tablet pc users spend 99% of
   their time, so it's quite important for me. Is this a hardware
   limitation, or are there plans to improve this? I thought hardware is
   capable of helping here, as Windows felt quite snappy even when
   rotated.

3. The i810 driver really doesn't like to start with the "Rotate" "CW"
   option and DRI. The server fails with

    (EE) I810(0): [drm] drmAddMap(front_handle) failed. Disabling DRI

   ... and a SEGV to make it very clear that it doesn't intend to
   continue. But, things are fine if I start without the rotate option
   and do a "xrandr -o right" afterwards, so I'm using that as a
   workaround.

4. XVideo works nicely, both in normal and rotated modes. Impressive! I
   can rotate the screen while a movie is playing!

5. DRI still seems to be a no-no. Tried enabling DRM, messages indicate
   acceleration is available, but glxgears only does 400fps, looks
   strange (the motion isn't smooth) and the entire machine hangs hard
   when I click the "close" button on the glxgears window.

(I tried the i915-20060403-linux.i386 snapshot for DRI support)

--J.