Re: [MAINTAINERS SUMMIT] Device Passthrough Considered Harmful?

Laurent Pinchart
2024-08-02T15:08:15Z

On Wed, Jul 31, 2024 at 03:15:39PM +0200, Daniel Vetter wrote:
> On Wed, 31 Jul 2024 at 13:55, Sakari Ailus wrote:
> > This is also very different from GPUs or accel devices that are built to be
> > user-programmable. If I'd compare ISPs to different devices, then the
> > closest match would probably be video codecs -- which also use V4L2.
>
> Really just aside, but I figured I should correct this. DRM supports
> plenty of video codecs. They're all tied to gpus, but the real reason
> really is that the hw has decent command submission support so that
> running the entire codec in userspace except the basic memory and
> batch execution and synchronization handling in the kernel is a
> feasible design. And actually good, because your kernel wont ever blow
> up trying to parse complex media formats because it just doesn't.

I don't think V4L2 codecs parse the bitstream in the kernel either, at
least not the recent ones.

--
Regards,

Laurent Pinchart