Re: [PATCH] Add virtio gpu driver.

  Hi,

quoted

Why attach the hotspot to the plane?  Wouldn't it make more sense to
make it a framebuffer property?

We don't have properties on the framebuffer. I guess you /could/ just add
it internally to struct drm_framebuffer, and not bother exposing to
userspace. I guess that would be a lot simpler,

Yes.  I can simply stick the hotspot into drm_framebuffer in
drm_mode_cursor_universal() and pick up the values in the driver's plane
update function.

 but it also means that
atomic userspace can't use hotspots before we add properties to fbs. And
doing that is a bit tricky since drm_framebuffer objects are meant to be
invariant - this assumption is deeply in-grained into the code all over
the place, everything just compares pointers when semantically it means to
compare the entire fb (including backing storage pointer/offsets and
everything).

Hmm, the hotspot location for a given cursor image is invariant too, so
I don't think that would be a big issue.

I'd expect userspace define a bunch of cursors, then switch between them
(instead of defining a single cursor, then constantly updating it).

cheers,
  Gerd