Re: [PATCH v4 7/8] utils/common: Set V4L2_SUBDEV_CLIENT_CAP_STREAMS for subdevs

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Tomi,

Thank you for the patch.

On Fri, Apr 21, 2023 at 03:44:27PM +0300, Tomi Valkeinen wrote:
> Do two things:
> 
> - Inform the kernel that we support streams with a call to
>   VIDIOC_SUBDEV_S_CLIENT_CAP
> 
> - Use the returns from VIDIOC_SUBDEV_S_CLIENT_CAP and
>   VIDIOC_SUBDEV_QUERYCAP to decide if streams are supported, and
>   return that via has_streams_support() method.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  utils/common/cv4l-helpers.h |  1 +
>  utils/common/v4l-helpers.h  | 17 +++++++++++++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/utils/common/cv4l-helpers.h b/utils/common/cv4l-helpers.h
> index 3cee372b..502df6ac 100644
> --- a/utils/common/cv4l-helpers.h
> +++ b/utils/common/cv4l-helpers.h
> @@ -82,6 +82,7 @@ public:
>  	bool has_rw() const { return v4l_has_rw(this); }
>  	bool has_streaming() const { return v4l_has_streaming(this); }
>  	bool has_ext_pix_format() const { return v4l_has_ext_pix_format(this); }
> +	bool has_streams_support() const { return subdev_supports_streams; }

The other functions don't have a "_support" suffix, I'd write
"has_stream()".

>  
>  	int querycap(v4l2_capability &cap, bool force = false)
>  	{
> diff --git a/utils/common/v4l-helpers.h b/utils/common/v4l-helpers.h
> index c09cd987..2dd7f061 100644
> --- a/utils/common/v4l-helpers.h
> +++ b/utils/common/v4l-helpers.h
> @@ -39,6 +39,7 @@ struct v4l_fd {
>  	bool have_selection;
>  	bool is_subdev;
>  	bool is_media;
> +	bool subdev_supports_streams;

Same here, and I would probably also drop the subdev_ prefix.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

>  
>  	int (*open)(struct v4l_fd *f, const char *file, int oflag, ...);
>  	int (*close)(struct v4l_fd *f);
> @@ -507,6 +508,12 @@ static inline int v4l_open(struct v4l_fd *f, const char *devname, bool non_block
>  
>  static inline int v4l_subdev_s_fd(struct v4l_fd *f, int fd, const char *devname)
>  {
> +	struct v4l2_subdev_client_capability clientcap = {};
> +	struct v4l2_subdev_capability subdevcap = {};
> +	bool subdev_streams;
> +	bool client_streams;
> +	int ret;
> +
>  	if (f->fd >= 0)
>  		f->close(f);
>  
> @@ -528,6 +535,16 @@ static inline int v4l_subdev_s_fd(struct v4l_fd *f, int fd, const char *devname)
>  	f->have_next_ctrl = false;
>  	f->have_selection = false;
>  
> +	ret = ioctl(f->fd, VIDIOC_SUBDEV_QUERYCAP, &subdevcap);
> +	subdev_streams = !ret && (subdevcap.capabilities & V4L2_SUBDEV_CAP_STREAMS);
> +
> +	clientcap.capabilities = V4L2_SUBDEV_CLIENT_CAP_STREAMS;
> +
> +	ret = ioctl(f->fd, VIDIOC_SUBDEV_S_CLIENT_CAP, &clientcap);
> +	client_streams = !ret && (clientcap.capabilities & V4L2_SUBDEV_CLIENT_CAP_STREAMS);
> +
> +	f->subdev_supports_streams = subdev_streams && client_streams;
> +
>  	return f->fd;
>  }
>  

-- 
Regards,

Laurent Pinchart