Re: [PATCH v1 1/9] media: v4l2-ctrls: Add user controls for StarFive JH7110 ISP

[Laurent Pinchart]

Hi Changhuang,

On Fri, Dec 15, 2023 at 01:55:09PM +0800, Changhuang Liang wrote:
> On 2023/12/14 19:39, Laurent Pinchart wrote:
> > On Wed, Dec 13, 2023 at 10:50:19PM -0800, Changhuang Liang wrote:
> >> Add a control base for StarFive JH7110 ISP driver controls, and reserve
> >> 32 controls，also add some controls for StarFive JH7110 ISP.
> > 
> > ISP parameters should be passed through parameters buffers, not V4L2
> > control. See for instance the V4L2_META_FMT_RK_ISP1_PARAMS format in the
> > mainline kernel, it describes how to store ISP parameters in a buffer.
> > The rkisp1 driver is an example of how this can be implemented.
> 
> That means I need to add a video output device before ISP subdev? And 
> use queue/dequeue buffer to get the ISP paremeters?

Yes, that is correct.

> > Please note that the ISP parameters need to be documented precisely,
> > regardless of how they're passed by userspace to the kernel. Even with
> > V4L2 controls, documentation would be needed. Please see below for
> > additional comments.
> 
> I will add annotations for this file next version.
> 
> >> Signed-off-by: Changhuang Liang <changhuang.liang@xxxxxxxxxxxxxxxx>
> >> ---
> >>  MAINTAINERS                        |   1 +
> >>  include/uapi/linux/jh7110-isp.h    | 342 +++++++++++++++++++++++++++++
> >>  include/uapi/linux/v4l2-controls.h |   6 +
> [...]

-- 
Regards,

Laurent Pinchart