Synchronization framework

[Maarten Lankhorst]

Hey,

For intel/nouveau hybrid graphics I'm interested in this since it
would allow me to synchronize between intel and nvidia cards
without waiting for rendering to complete.

I'm worried about the api though, nouveau and intel already
have existing infrastructure to deal with fencing so exposing
additional ioctl's will complicate the implementation. Would
it be possible to never expose this interface to userspace
but keep it inside the kernel only?

nouveau_gem_ioctl_pushbuf is what's used for nouveau.
If any dmabuf synch framework could hook into that then
userspace would never have to act differently on shared bo's.

I haven't looked at intel and amd, but from a quick glance
it seems like they already implement fencing too, so just
some way to synch up the fences on shared buffers seems
like it could benefit all graphics drivers and the whole
userspace synching could be done away with entirely.

Cheers,
Maarten