When a software fallback has completed, usermode must notify the kernel so
that any scanout buffers can be synchronized. This ioctl should be called
whenever a fallback completes to flush CPU and chipset caches.
Thanks to Thomas Hellstrom for catching the issue, no thanks to the kernel
developer who authoritatively told me that they would get restarted on their
own.
This is the create (may want location flags), pread/pwrite/mmap
(performance tuning hints), and set_domain (will 32 bits be enough for
everyone?) ioctls. Left in the generic set are just flink/open/close.
The 2D driver must be updated for this change, and API but not ABI is broken
for 3D. The driver version is bumped to mark this.
The code was discarding the dri_bo_gem structure and saving only the kernel
handle. This lost the mmap address, causing pain when the next buffer user
wanted to map the buffer.
