[libcamera-devel] [PATCH 2/3] pipeline: ipa: raspberrypi: Correctly report available control limits

[Kieran Bingham]

Quoting Naushir Patuck via libcamera-devel (2022-06-10 13:25:32)
> The ipa currently advertises a static ControlInfoMap to specify the available
> controls and their limits. Fix this limitation by having the IPA populate a new
> ControlInfoMap with updated limits for ExposureTime, AnalogueGain, and
> FrameDurationLimits controls based on the current sensor mode. This new
> ControlInfoMap is then returned back to the pipeline handler and available to
> the application after a successful Camera::Configure() call.
> 
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> ---
>  include/libcamera/ipa/raspberrypi.mojom       |  1 +
>  src/ipa/raspberrypi/raspberrypi.cpp           | 24 ++++++++++++++++---
>  .../pipeline/raspberrypi/raspberrypi.cpp      |  3 +++
>  3 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/include/libcamera/ipa/raspberrypi.mojom b/include/libcamera/ipa/raspberrypi.mojom
> index 77f52c282b0f..c0de435b7b33 100644
> --- a/include/libcamera/ipa/raspberrypi.mojom
> +++ b/include/libcamera/ipa/raspberrypi.mojom
> @@ -45,6 +45,7 @@ struct IPAConfig {
>  
>  struct IPAConfigResult {

Aha, I see the precedent for "Result" now. so perhaps it's more suitable
in the previous patch than I realised.


>         float modeSensitivity;
> +       libcamera.ControlInfoMap controlInfo;
>  };
>  
>  struct StartConfig {
> diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> index 089528f5e126..295f6b735dc0 100644
> --- a/src/ipa/raspberrypi/raspberrypi.cpp
> +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> @@ -74,8 +74,6 @@ constexpr Duration controllerMinFrameDuration = 1.0s / 30.0;
>  /* List of controls handled by the Raspberry Pi IPA */
>  static const ControlInfoMap::Map ipaControls{
>         { &controls::AeEnable, ControlInfo(false, true) },
> -       { &controls::ExposureTime, ControlInfo(0, 999999) },
> -       { &controls::AnalogueGain, ControlInfo(1.0f, 32.0f) },
>         { &controls::AeMeteringMode, ControlInfo(controls::AeMeteringModeValues) },
>         { &controls::AeConstraintMode, ControlInfo(controls::AeConstraintModeValues) },
>         { &controls::AeExposureMode, ControlInfo(controls::AeExposureModeValues) },
> @@ -89,7 +87,6 @@ static const ControlInfoMap::Map ipaControls{
>         { &controls::Sharpness, ControlInfo(0.0f, 16.0f, 1.0f) },
>         { &controls::ColourCorrectionMatrix, ControlInfo(-16.0f, 16.0f) },
>         { &controls::ScalerCrop, ControlInfo(Rectangle{}, Rectangle(65535, 65535, 65535, 65535), Rectangle{}) },
> -       { &controls::FrameDurationLimits, ControlInfo(INT64_C(1000), INT64_C(1000000000)) },
>         { &controls::draft::NoiseReductionMode, ControlInfo(controls::draft::NoiseReductionModeValues) }
>  };
>  
> @@ -446,6 +443,27 @@ int IPARPi::configure(const IPACameraSensorInfo &sensorInfo,
>         ASSERT(controls);
>         *controls = std::move(ctrls);
>  
> +       /*
> +        * Apply the correct limits to the exposure, gain and frame duration controls
> +        * based on the current sensor mode.
> +        */
> +       ControlInfoMap::Map ctrlMap = ipaControls;
> +       const Duration minSensorFrameDuration = mode_.min_frame_length * mode_.line_length;
> +       const Duration maxSensorFrameDuration = mode_.max_frame_length * mode_.line_length;
> +       ctrlMap.emplace(&controls::FrameDurationLimits,
> +                       ControlInfo(static_cast<int64_t>(minSensorFrameDuration.get<std::micro>()),
> +                                   static_cast<int64_t>(maxSensorFrameDuration.get<std::micro>())));
> +
> +       ctrlMap.emplace(&controls::AnalogueGain,
> +                       ControlInfo(1.0f, static_cast<float>(helper_->Gain(maxSensorGainCode_))));
> +
> +       const uint32_t exposureMin = sensorCtrls_.at(V4L2_CID_EXPOSURE).min().get<int32_t>();
> +       const uint32_t exposureMax = sensorCtrls_.at(V4L2_CID_EXPOSURE).max().get<int32_t>();
> +       ctrlMap.emplace(&controls::ExposureTime,
> +                       ControlInfo(static_cast<int32_t>(helper_->Exposure(exposureMin).get<std::micro>()),
> +                                   static_cast<int32_t>(helper_->Exposure(exposureMax).get<std::micro>())));
> +
> +       result->controlInfo = ControlInfoMap(std::move(ctrlMap), controls::controls);


aha, this means applications can't read the exposure time / gain
controls before the camera is configured.

I think that sounds 'correct' - but I wonder if we need to make that
clear in some documentation somewhere, or somehow in an extension of
'simple-cam' showing how to manage camera controls. (Not to block this
patch of course).


We should make sure applications realise they have to recheck controls
after a configuration operation. (Maybe that's obvious .. I'm not sure).

I was dwelling on if we should only send the updates to the
ControlInfoMap over the IPC mechanism, but I don't think this is
critical path, and it's simpler to send the whole updated map - so:


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

>         return 0;
>  }
>  
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index d980c1a71dd8..4596f2babcea 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -940,6 +940,9 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
>         /* Store the mode sensitivity for the application. */
>         data->properties_.set(properties::SensorSensitivity, result.modeSensitivity);
>  
> +       /* Update the controls that the Raspberry Pi IPA can handle. */
> +       data->controlInfo_ = result.controlInfo;
> +
>         /* Setup the Video Mux/Bridge entities. */
>         for (auto &[device, link] : data->bridgeDevices_) {
>                 /*
> -- 
> 2.25.1
>