[virglrenderer-devel] multiprocess model and GL

[Gerd Hoffmann]

  Hi,

> > The vulkan driver has object ids though, and trying to hide that creates
> > a bunch of limitations.  For example it forces creating object and
> > resource at the same time.
> 
> You mean it forces allocation and resource creation to occur at the
> same time?  No.
> Essentially, there's three commands we can put in the command buffer:
> 
> (1) ALLOCATE
> (2) ASSIGN_OBJ_ID (setup [obj_id] --> [struct resource] mapping)
> (3) GET_OBJ_ID  (lookup [obj_id] --> [struct resource] mapping)
> 
> Right now, VIRTIO_GPU_CMD_SUBMIT_3D does (1) and (2) [ASSIGN_OBJ_ID is
> implicit in the command buffer].

(1) and (2) are not separate steps.  You need some way to address your
object, and obj_id provides exactly that.

> virgl_renderer_resource_create_blob(resid, size, flags, obj_id)
> essentially does (3).

Yes, and establish res_id -> struct resource mapping.

> With virgl_renderer_resource_create_blob(resid, size, flags, void
> *resource_create_3d, int ndw, ..):
> 
> - setup [res_id] --> [struct resource] from a prior object via (3),

Hmm, how do you want find your resource here when it has no obj_id?

> - allocate and setup [res_id] --> [struct resource] only via (1)
> - allocate and setup both  [res_id] --> [struct resource], [obj_id]
> -->  [struct resource] mapping via (1) and (2)
> 
> All user space has to do is specify the right command buffer (which
> should be less than 64 bytes).

How does userspace figure the res_id?

cheers,
  Gerd