[libcamera-devel] [PATCH v4 4/5] libcamera: properties: Provide a Devices camera property

[Barnabás Pőcze]

Hi


2023. június 15., csütörtök 19:26 keltezéssel, Kieran Bingham via libcamera-devel <libcamera-devel at lists.libcamera.org> írta:

> Provide a new Camera property that allows pipeline handlers to list any
> kernel device used to operate the camera. This allows other frameworks
> and daemons such as PipeWire to better understand the resources consumed
> by a Camera and consider ignoring those resources when enumerating
> camera devices on a system.
> 
> Tested-by: Ashok Sidipotu <ashok.sidipotu at collabora.com>
> Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> ---
> v4:
>  - Report that different cameras may report identical devices
>  - Rename to SystemDevices
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
>  src/libcamera/property_ids.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/src/libcamera/property_ids.yaml b/src/libcamera/property_ids.yaml
> index cb55e0ed2283..ef1dfd322db1 100644
> --- a/src/libcamera/property_ids.yaml
> +++ b/src/libcamera/property_ids.yaml
> @@ -690,6 +690,15 @@ controls:
>          that is twice that of the full resolution mode. This value will be valid
>          after the configure method has returned successfully.
> 
> +  - SystemDevices:
> +      type: int64_t
> +      size: [n]
> +      description: |
> +        A list of integer values of type dev_t denoting major and minor device
> +        number of the underlying devices used in the operation of this camera.

I am no native speaker of English, but to me any of

 - ... denoting [the] major and minor device number of the underlying ...
 - ... denoting major and minor device number[s] of the underlying ...

sounds a bit better.


> +
> +        Different cameras may report identical devices.

I am wondering how this statement is reconciled with the fact that `camerasByDevnum_`
is just a simple map, and not a multimap; and that `CameraManager::get(dev_t)`
returns a single camera. I know this is not really relevant for this patch, sorry,
but maybe it's worth looking into.


> +
>    # ----------------------------------------------------------------------------
>    # Draft properties section
> 
> --
> 2.34.1


Regards,
Barnabás Pőcze