Dave Airlie a écrit :
>>I still only see "agp_backend_acquire failed on atomic read".
>
> do you see how many atomic inc and atomic decs there is?
> 
> send me the full dmesg...
> thanks,
> Dave.

The agp_in_use field of the bridge structure is never initialized.
That's the reason why atomic_read fails to read 0.

In vanilla, the bridge is allocated as a static global variable, and
thus initialized to 0 at init. In -mm, the bridge is kmalloc'ed, and
thus not initialized.

The attached patch fixes it and solves my problem (when combined with
http://lkml.org/lkml/2005/1/7/377). DRM is back with good performance.

Regards
Brice