Re: [PATCH v7 07/14] media: v4l2-subdev: Move subdev client capabilities into a new struct

On Fri, Aug 07, 2026 at 03:24:02PM +0300, Sakari Ailus wrote:
> Add struct v4l2_subdev_client_info to hold sub-device client capability
> bits that used to be stored in the client_caps field of struct
> v4l2_subdev_fh.
> 
> The intent is to enable passing this struct to sub-device pad operation
> callbacks for capability information. The main reason why this is a new
> struct instead of a u64 field is that modifying the callback arguments
> requires touching almost every sub-device driver and that is desirable to
> avoid in the future, should more than the client capability bits need to
> be known to the callbacks.
> 
> Signed-off-by: Sakari Ailus <[email protected]>
> Reviewed-by: Mirela Rabulea <[email protected]>
> Reviewed-by: Frank Li <[email protected]>

Reviewed-by: Laurent Pinchart <[email protected]>

> ---
>  drivers/media/v4l2-core/v4l2-subdev.c |  8 ++++----
>  include/media/v4l2-subdev.h           | 12 ++++++++++--
>  2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index e9f81b9be9e2..f392586d5dba 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -611,7 +611,7 @@ subdev_ioctl_get_state(struct v4l2_subdev *sd, struct v4l2_subdev_fh *subdev_fh,
>  	case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {
>  		struct v4l2_subdev_frame_interval *fi = arg;
>  
> -		if (!(subdev_fh->client_caps &
> +		if (!(subdev_fh->ci.caps &
>  		      V4L2_SUBDEV_CLIENT_CAP_INTERVAL_USES_WHICH))
>  			fi->which = V4L2_SUBDEV_FORMAT_ACTIVE;
>  
> @@ -650,7 +650,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  	struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);
>  	bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
>  	bool streams_subdev = sd->flags & V4L2_SUBDEV_FL_STREAMS;
> -	bool client_supports_streams = subdev_fh->client_caps &
> +	bool client_supports_streams = subdev_fh->ci.caps &
>  				       V4L2_SUBDEV_CLIENT_CAP_STREAMS;
>  	int rval;
>  
> @@ -1117,7 +1117,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  	case VIDIOC_SUBDEV_G_CLIENT_CAP: {
>  		struct v4l2_subdev_client_capability *client_cap = arg;
>  
> -		client_cap->capabilities = subdev_fh->client_caps;
> +		client_cap->capabilities = subdev_fh->ci.caps;
>  
>  		return 0;
>  	}
> @@ -1137,7 +1137,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  		client_cap->capabilities &= (V4L2_SUBDEV_CLIENT_CAP_STREAMS |
>  					     V4L2_SUBDEV_CLIENT_CAP_INTERVAL_USES_WHICH);
>  
> -		subdev_fh->client_caps = client_cap->capabilities;
> +		subdev_fh->ci.caps = client_cap->capabilities;
>  
>  		return 0;
>  	}
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index d9dca6905b33..04fa23b9a651 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -734,6 +734,14 @@ struct v4l2_subdev_state {
>  	struct v4l2_subdev_stream_configs stream_configs;
>  };
>  
> +/**
> + * struct v4l2_subdev_client_info - Sub-device client information
> + * @caps: bitmask of ``V4L2_SUBDEV_CLIENT_CAP_*``
> + */
> +struct v4l2_subdev_client_info {
> +	u64 caps;
> +};
> +
>  /**
>   * struct v4l2_subdev_pad_ops - v4l2-subdev pad level operations
>   *
> @@ -1130,14 +1138,14 @@ struct v4l2_subdev {
>   * @vfh: pointer to &struct v4l2_fh
>   * @state: pointer to &struct v4l2_subdev_state
>   * @owner: module pointer to the owner of this file handle
> - * @client_caps: bitmask of ``V4L2_SUBDEV_CLIENT_CAP_*``
> + * @ci: sub-device client info related to this file handle
>   */
>  struct v4l2_subdev_fh {
>  	struct v4l2_fh vfh;
>  	struct module *owner;
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  	struct v4l2_subdev_state *state;
> -	u64 client_caps;
> +	struct v4l2_subdev_client_info ci;
>  #endif
>  };
>  

-- 
Regards,

Laurent Pinchart