[PATCH v2 2/2] libcamera: pipeline: uvcvideo: Fix `ExposureTimeMode` control setting

[Jacopo Mondi]

Hi Barnabás

 nice fix

On Mon, Feb 17, 2025 at 06:53:39PM +0000, Barnabás Pőcze wrote:
> The mapping in `UVCCameraData::processControl()` is not entirely correct
> because the control value is retrieved as a `bool` instead of `int32_t`.
> Additionally, the available modes are not taken into account.
>
> To fix this, retrieve the control with the proper type - `int32_t` -,
> and use the available modes stored in `UVCCameraData` to determine
> which value to use for the V4L2 control.

With the assertion removal as suggested by Kieran
Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

(I actually wonder if it is possible to receive a
controls::ExposureTimeModeAuto
!data->availableExposureModes_[V4L2_EXPOSURE_AUTO] &&
!data->availableExposureModes_[V4L2_EXPOSURE_APERTURE_PRIORITY])

as the Camera shouldn't register  controls::ExposureTimeModeAuto in
the ::controls() ControlInfoMap...

However, checking for this surely doesn't hurt.

>
> Fixes: bad8d591f8acfa ("libcamera: uvcvideo: Register ExposureTimeMode control")
> Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>
> ---
>  src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 38 +++++++++++++++-----
>  1 file changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> index 1f604b91e..adab6aa18 100644
> --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> @@ -103,8 +103,8 @@ public:
>  	bool match(DeviceEnumerator *enumerator) override;
>
>  private:
> -	int processControl(ControlList *controls, unsigned int id,
> -			   const ControlValue &value);
> +	int processControl(UVCCameraData *data, ControlList *controls,
> +			   unsigned int id, const ControlValue &value);
>  	int processControls(UVCCameraData *data, Request *request);
>
>  	bool acquireDevice(Camera *camera) override;
> @@ -297,8 +297,8 @@ void PipelineHandlerUVC::stopDevice(Camera *camera)
>  	data->video_->releaseBuffers();
>  }
>
> -int PipelineHandlerUVC::processControl(ControlList *controls, unsigned int id,
> -				       const ControlValue &value)
> +int PipelineHandlerUVC::processControl(UVCCameraData *data, ControlList *controls,
> +				       unsigned int id, const ControlValue &value)
>  {
>  	uint32_t cid;
>
> @@ -342,10 +342,30 @@ int PipelineHandlerUVC::processControl(ControlList *controls, unsigned int id,
>  	}
>
>  	case V4L2_CID_EXPOSURE_AUTO: {
> -		int32_t ivalue = value.get<bool>()
> -			       ? V4L2_EXPOSURE_APERTURE_PRIORITY
> -			       : V4L2_EXPOSURE_MANUAL;
> -		controls->set(V4L2_CID_EXPOSURE_AUTO, ivalue);
> +		v4l2_exposure_auto_type exposureMode = {};
> +
> +		switch (value.get<int32_t>()) {
> +		case controls::ExposureTimeModeAuto:
> +			if (data->availableExposureModes_[V4L2_EXPOSURE_AUTO])
> +				exposureMode = V4L2_EXPOSURE_AUTO;
> +			else if (data->availableExposureModes_[V4L2_EXPOSURE_APERTURE_PRIORITY])
> +				exposureMode = V4L2_EXPOSURE_APERTURE_PRIORITY;
> +			else
> +				ASSERT(false);
> +			break;
> +		case controls::ExposureTimeModeManual:
> +			if (data->availableExposureModes_[V4L2_EXPOSURE_MANUAL])
> +				exposureMode = V4L2_EXPOSURE_MANUAL;
> +			else if (data->availableExposureModes_[V4L2_EXPOSURE_SHUTTER_PRIORITY])
> +				exposureMode = V4L2_EXPOSURE_SHUTTER_PRIORITY;
> +			else
> +				ASSERT(false);
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +
> +		controls->set(V4L2_CID_EXPOSURE_AUTO, exposureMode);
>  		break;
>  	}
>
> @@ -383,7 +403,7 @@ int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
>  	ControlList controls(data->video_->controls());
>
>  	for (const auto &[id, value] : request->controls())
> -		processControl(&controls, id, value);
> +		processControl(data, &controls, id, value);
>
>  	for (const auto &ctrl : controls)
>  		LOG(UVC, Debug)
> --
> 2.48.1
>
>