[PATCH v1 1/5] ipa: rkisp1: awb: Clamp gains to machine limits

[Paul Elder]

On Fri, Jul 12, 2024 at 04:32:02PM +0200, Stefan Klug wrote:
> When the color gains where set manually it was possible to specify a

s/where/are/

> gain that wrapped the hardware limits. It would also be possible to
> further tune the floating point limits, but that is an error prone
> approach. So the limits are imposed on the integers, just before writing
> to the hardware. This noticeably reduces some oscillations in the awb
> regulation.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>

tbh these should be protected against once in the kernel and against in
the ControlInfo but until those are fixed we need this.

Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>

> ---
>  src/ipa/rkisp1/algorithms/awb.cpp | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
> index a01fe5d90973..1a5d4776970a 100644
> --- a/src/ipa/rkisp1/algorithms/awb.cpp
> +++ b/src/ipa/rkisp1/algorithms/awb.cpp
> @@ -120,10 +120,14 @@ void Awb::prepare(IPAContext &context, const uint32_t frame,
>  		frameContext.awb.gains.blue = context.activeState.awb.gains.automatic.blue;
>  	}
>  
> -	params->others.awb_gain_config.gain_green_b = 256 * frameContext.awb.gains.green;
> -	params->others.awb_gain_config.gain_blue = 256 * frameContext.awb.gains.blue;
> -	params->others.awb_gain_config.gain_red = 256 * frameContext.awb.gains.red;
> -	params->others.awb_gain_config.gain_green_r = 256 * frameContext.awb.gains.green;
> +	params->others.awb_gain_config.gain_green_b =
> +		std::clamp<int>(256 * frameContext.awb.gains.green, 0, 0x3ff);
> +	params->others.awb_gain_config.gain_blue =
> +		std::clamp<int>(256 * frameContext.awb.gains.blue, 0, 0x3ff);
> +	params->others.awb_gain_config.gain_red =
> +		std::clamp<int>(256 * frameContext.awb.gains.red, 0, 0x3ff);
> +	params->others.awb_gain_config.gain_green_r =
> +		std::clamp<int>(256 * frameContext.awb.gains.green, 0, 0x3ff);
>  
>  	/* Update the gains. */
>  	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
> -- 
> 2.43.0
>