[PATCH 11/12] ipa: rkisp1: agc: Correctly clamp maximum shutter speed

[Kieran Bingham]

Quoting Laurent Pinchart (2024-06-16 17:39:09)
> The sensor's maximum shutter speed is clamped by the maximum frame
> duration specified in requests. If the requested maximum frame duration
> is lower than the sensor's minimum shutter speed, the Agc::process()
> function will pass a minimum value higher than the maximum to the
> setLimits() function, resulting in an assertion failure. Fix it by
> clamping the value to both the lower and the upper bounds.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/ipa/rkisp1/algorithms/agc.cpp | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
> index 5b917557b887..0018c43f18cf 100644
> --- a/src/ipa/rkisp1/algorithms/agc.cpp
> +++ b/src/ipa/rkisp1/algorithms/agc.cpp
> @@ -420,8 +420,10 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
>                        [](uint32_t x) { return x >> 4; });
>         expMeans_ = { params->ae.exp_mean, context.hw->numAeCells };
>  
> -       utils::Duration maxShutterSpeed = std::min(context.configuration.sensor.maxShutterSpeed,
> -                                                  frameContext.agc.maxFrameDuration);
> +       utils::Duration maxShutterSpeed =
> +               std::clamp(frameContext.agc.maxFrameDuration,
> +                          context.configuration.sensor.minShutterSpeed,
> +                          context.configuration.sensor.maxShutterSpeed);
>         setLimits(context.configuration.sensor.minShutterSpeed,
>                   maxShutterSpeed,

I'm somehow confused here, as we're passing sensor.minShutterSpeed in
here as well. Does that now become redundant? Or could/should this
clamping be done within setLimits? Does the other call site of setLimits
experience the same issue?



>                   context.configuration.sensor.minAnalogueGain,
> -- 
> Regards,
> 
> Laurent Pinchart
>