i810 problems and questions

Lukas Hejtmanek xhejtman at fi.muni.cz
Fri Jul 7 10:02:12 PDT 2006

On Fri, Jul 07, 2006 at 06:32:12PM +0200, Jan Rychter wrote:
> 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.

I think this is because of low memory bandwith and disabled offscreen pixmaps
when rotation is in action. (Framebuffer is taken as texture wich is then mapped
onto screen and rotated. Looks like i830 HW does not support real rotation in

> 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.

Looks like it is trying to call drmAddMap twice. Hmm, could you try latest git

> 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.

What version of Mesa libs are you using? The non smooth motion I noticed with
current Mesa CVS HEAD. 

Lukáš Hejtmánek

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