[libcamera-devel] [PATCH v3 3/4] android: Override camera as "Internal" provided found in HAL config

[Laurent Pinchart]

Hi Umang,

Thank you for the patch.

On Mon, Aug 02, 2021 at 03:21:14PM +0530, Umang Jain wrote:
> On 8/2/21 2:16 PM, paul.elder at ideasonboard.com wrote:
> > On Fri, Jul 30, 2021 at 04:31:53PM +0530, Umang Jain wrote:
> >> Currently, all UVC cameras are reported with CameraLocationExternal [1]
> >> by libcamera-core, since there is no universal information or standard,
> >
> > s/,$//
> >
> >> to know the location of these cameras. However, in the libcamera HAL
> >> layer, we can make an informed decision whether its external or
> >
> > s/its/it's/
> >
> >> internal, simply by checking the presence of it in the HAL
> >
> > s/the presence of it/its presence/
> >
> >> configuration file.
> >>
> >> If the camera is found to be present in the HAL configuration file,
> >
> > s/to be present//
> >
> >> treat it as internal. CameraHalManager will now assign the numerical id
> >> of the camera accordingly, based on which the facing of the camera is set
> >
> > I didn't think the facing of the camera affects the id?
> 
> Well, it should be kept in sync. If the camera is internal (id < 1000), 
> but it's facing is set to be external (as per checks in CameraDevice), 
> then these are not in sync. We need to take care of that.
> 
> I don't think anything bad will happen if these are out of sync. But why 
> should we allow it to be out-of-sync if we handle it gracefully?

I agree, it's best to keep them in sync.

> >> as well (as per the HAL config file) while initializing the CameraDevice
> >> wrapper.
> >
> > I don't quite understand this last part.
>
> So in the  CameraDevice::initialize(), the facing of the camera is set. 
> If properties::Location doesn't match the location in the HAL config, 
> CameraDevice complains a warning.
> 
> But, we know that for UVC properties:::Location won't be matching the 
> HAL config. In that case we rely on id assigned by CameraManager to see 
> if its a  internal camera or not. If yes, we just assign facing whatever 
> is mentioned in the HAL config file :)

The last sentence of the commit message can probably be clarified a bit.
How about this ?

"The CameraHalManager will now assign the numerical id of the camera
accordingly when initializing the CameraDevice, based on the camera
facing value set in the HAL config file."

> >> [1] 76809320bb1a ("libcamera: pipeline: uvcvideo: Treat all UVC cameras
> >>                     as external")
> >>
> >> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> >> ---
> >>   src/android/camera_device.cpp      | 13 ++++++++++++-
> >>   src/android/camera_hal_manager.cpp | 17 +++++++++++++++++
> >>   2 files changed, 29 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> >> index 678cde23..394ebc84 100644
> >> --- a/src/android/camera_device.cpp
> >> +++ b/src/android/camera_device.cpp
> >> @@ -330,7 +330,18 @@ int CameraDevice::initialize(const CameraConfigData *cameraConfigData)
> >>   			facing_ = CAMERA_FACING_BACK;
> >>   			break;
> >>   		case properties::CameraLocationExternal:
> >> -			facing_ = CAMERA_FACING_EXTERNAL;
> >> +			/*
> >> +			 * If the camera is reported as external, but
> >> +			 * the CameraHalManager has overriden it, use
> >> +			 * what is reported in the configuration file.
> >> +			 * This typically happens for UVC cameras
> >> +			 * reported as 'External' by libcamera but
> >> +			 * installed in fixed position on the device.
> >> +			 */

This could be reflowed to 80 columns.

> >> +			if (id_ < 1000 && cameraConfigData->facing != -1)

Is the id_ check needed ? If libcamera reports the camera as external
and the camera data overrides the facing value, the id will always be <
1000, won't it ?

> >> +			       facing_ = cameraConfigData->facing;
> >> +			else
> >> +			       facing_ = CAMERA_FACING_EXTERNAL;
> >>   			break;
> >>   		}
> >>   
> >> diff --git a/src/android/camera_hal_manager.cpp b/src/android/camera_hal_manager.cpp
> >> index b364f62a..cce98fad 100644
> >> --- a/src/android/camera_hal_manager.cpp
> >> +++ b/src/android/camera_hal_manager.cpp
> >> @@ -145,6 +145,23 @@ void CameraHalManager::cameraAdded(std::shared_ptr<Camera> cam)
> >>   	}
> >>   
> >>   	const CameraConfigData *cameraConfigData = halConfig_.cameraConfigData(cam->id());
> >> +
> >> +	/*
> >> +	 * Some cameras whose location is reported by libcamera as external may
> >> +	 * actually be internal to the device. This is common with UVC cameras
> >> +	 * that are integrated in a laptop. In that case the real location
> >> +	 * should be specified in the configuration file.
> >> +	 *
> >> +	 * If the camera location is external and a configuration
> >> +	 * entry exists for it, override its location.

You could also reflow this to 80 columns.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> >> +	 */
> >> +	if (isCameraNew && isCameraExternal) {
> >> +		if (cameraConfigData && cameraConfigData->facing != -1) {
> >> +			isCameraExternal = false;
> >> +			id = numInternalCameras_;
> >> +		}
> >> +	}
> >> +
> >>   	if (!isCameraExternal && !cameraConfigData) {
> >>   		LOG(HAL, Error)
> >>   			<< "HAL configuration entry for internal camera "

-- 
Regards,

Laurent Pinchart