[libcamera-devel] [PATCH] ipa: raspberrypi: awb: Better handling of how we disable AWB

[Laurent Pinchart]

Hi David,

Thank you for the patch.

On Fri, Feb 04, 2022 at 09:24:35AM +0000, David Plowman wrote:
> We now handle disabling ("pausing") AWB in the same way as
> AEC/AGC. Instead of letting the pause flag be set so that the code
> never runs at all, we instead fix the manual settings to the current
> values (but continue to be called).
> 
> The algorithm does not restart any calculations in this state, but
> continues to add AWB metadata to every frame. Therefore certain other
> algorithms that want to know it (CCM and ALSC, for example) can still
> find it.

That seems to be a good step forward.

Given that the only algorithms to ever be paused are AGC and AWB, it
seems that we could remove the IsPaused() function as it will always
return false (hardcoded for AGC and AWB, and because Pause() is never
called for all the other algorithms). This can be done on top.

> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/ipa/raspberrypi/controller/rpi/awb.cpp | 21 +++++++++++++++++++++
>  src/ipa/raspberrypi/controller/rpi/awb.hpp |  4 ++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/src/ipa/raspberrypi/controller/rpi/awb.cpp b/src/ipa/raspberrypi/controller/rpi/awb.cpp
> index 5cfd33a3..1ad912c7 100644
> --- a/src/ipa/raspberrypi/controller/rpi/awb.cpp
> +++ b/src/ipa/raspberrypi/controller/rpi/awb.cpp
> @@ -172,6 +172,27 @@ void Awb::Initialise()
>  	async_results_ = sync_results_;
>  }
>  
> +bool Awb::IsPaused() const
> +{
> +	return false;
> +}
> +
> +void Awb::Pause()
> +{
> +	// "Pause" by fixing everything to the most recent values.
> +	manual_r_ = sync_results_.gain_r = prev_sync_results_.gain_r;
> +	manual_b_ = sync_results_.gain_b = prev_sync_results_.gain_b;
> +	sync_results_.gain_g = prev_sync_results_.gain_g;
> +	sync_results_.gain_g = prev_sync_results_.gain_g;

Once should be enough :-)

> +	sync_results_.temperature_K = prev_sync_results_.temperature_K;
> +}
> +
> +void Awb::Resume()
> +{
> +	manual_r_ = 0.0;
> +	manual_b_ = 0.0;
> +}
> +
>  unsigned int Awb::GetConvergenceFrames() const
>  {
>  	// If not in auto mode, there is no convergence
> diff --git a/src/ipa/raspberrypi/controller/rpi/awb.hpp b/src/ipa/raspberrypi/controller/rpi/awb.hpp
> index 8af1f27c..ac3dca6f 100644
> --- a/src/ipa/raspberrypi/controller/rpi/awb.hpp
> +++ b/src/ipa/raspberrypi/controller/rpi/awb.hpp
> @@ -83,6 +83,10 @@ public:
>  	char const *Name() const override;
>  	void Initialise() override;
>  	void Read(boost::property_tree::ptree const &params) override;
> +	// AWB handles "pausing" for itself.
> +	bool IsPaused() const override;
> +	void Pause() override;
> +	void Resume() override;
>  	unsigned int GetConvergenceFrames() const override;
>  	void SetMode(std::string const &name) override;
>  	void SetManualGains(double manual_r, double manual_b) override;

-- 
Regards,

Laurent Pinchart