[PATCH 40/59] drm/vram-helper: Drop drm_gem_prime_export/import

[Gerd Hoffmann]

  Hi,

> > > Second one is drm_driver->fops->mmap. That one we need to keep, but this
> > > isn't mmap on a buffer, but mmap on the entire drm_device. The one which
> > > should be replaced by drm_gem_object_funcs.vm_ops is
> > > drm_driver->gem_vm_ops.
> >
> > Hmm, seems ttm hasn't something I can hook into drm_driver->gem_vm_ops ...
> 
> ttm_bo_vm_ops seems to be the thing you want.

Wouldn't work as-is, but when ttm bo are a subclass of gem bos should
be possible to create something usable based on it.

Related question: why there is no drm_gem_object_funcs.mmap() callback?
I think it would make sense to have a callback where the bo-specific
setup can be done, i.e. what ttm_bo_mmap() or drm_gem_shmem_mmap() are
doing, and have some generic function which basically does the lookup,
then dispatches.

cheers,
  Gerd