On Wed, Jul 31, 2024 at 03:15:39PM +0200, Daniel Vetter wrote:

On Wed, 31 Jul 2024 at 13:55, Sakari Ailus wrote:

quoted

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