Re: Proposed updates and guidelines for MPEG-2, H.264 and H.265 stateless support

Boris Brezillon
2019-06-04T09:05:32Z

On Tue, 4 Jun 2019 10:55:03 +0200
Thierry Reding <thierry.reding@gmail.com> wrote:

> On Mon, Jun 03, 2019 at 02:52:44PM -0400, Nicolas Dufresne wrote:
> [...]
> > There is one thing that come up though, if we enable per-frame decoding
> > on top of per-slice decoder (like Cedrus), won't we force userspace to
> > always compute l0/l1 even though the HW might be handling that ? Shall
> > we instead pass the modification list and implement the non-parsing
> > bits of applying the modifications in the kernel ?
>
> Applying the modifications is a standard procedure, right? If it's
> completely driver-agnostic, it sounds to me like the right place to
> perform the operation is in userspace.

Well, the counter argument to that is "drivers know better what's
needed by the HW", and if we want to avoid doing useless work without
having complex caps checking done in userspace, doing this task
kenel-side makes sense.