Bug#541235: xserver-xorg-video-ati: Random Lockups when DRI enabled

[Alex Deucher]

2009/8/17 Stefano <pietranera at gmail.com>:
> On Thu, 2009-08-13 at 11:01 +0200, Michel Dänzer wrote:
>> Hmm. One thing I notice is that there's almost no EXA offscreen memory,
>> due to your enormous Virtual directive. Normally this should only affect
>> performance, not correctness, but it might be worth trying a smaller
>> maximum desktop size just in case.
>>
>
> Hello,
>
> I tried different configurations for my Virtual screen. Here are the
> logs (hope I've picked the right lines!):
>
> Virtual: 2944x1848 (BIG)
> (II) EXA(0): Offscreen pixmap area of 786432 bytes
>
> VirtuaL: NONE
> (II) EXA(0): Offscreen pixmap area of 11436032 bytes
>
> Virtual: 1920x1848 (VERTICAL)
> (II) EXA(0): Offscreen pixmap area of 12255232 bytes
>
> VirtuaL: 2944x1080 (HORIZONTAL)
> (II) EXA(0): Offscreen pixmap area of 14352384 bytes
>
> I thought that the configuration with most free memory would have been
> the second one (no virtual screen) but surprisingly to me it is not the
> case.
>

By default xrandr 1.2 grabs a square framebuffer so rotation will work
(e.g., 1920x1920).

> Now I'm using the 2944x1080 (HORIZONTAL) Virtual screen with AGPMode 4
> (default) and DRI enabled. The issues I had seem to be gone. However I
> cannot activate Compositing when I use my external screen since X
> consumes almost the 80% of the CPU when I move the windows around the
> screen. If I use my laptop monitor (1024x768) Compositing works quite
> well, although I experienced some lock-ups when I tried to modify the
> options of gnome-do in order to activate the "Docky".
>

Your desktop is larger than the coordinate limits of the texture
engine so it's likely falling back to software.

> Can we consider this bug closed?
>

Yes.

> Can you do anything to prevent users to make the same mistakes I made?

radeon KMS (kernel modesetting) includes a unified memory manager that
will allow you to resize your desktop on the fly without needing to
add the virtual stuff.

Alex