[libcamera-devel] [PATCH] ipa: ipu3: af: Set default grid block width to the minimum value

[Jean-Michel Hautbois]

Hi Kate,

On 22/03/2022 02:31, Kate Hsuan via libcamera-devel wrote:
> Since x	coordinate is incorrectly computed by a kernel issue, the block width
> should be set to 4 to prevent using the second stripe when setting the AF scene
> to the centre of the image. A kernel patch had fixed this issue. Therefore, this
> value can be set to the default minimum value.

If this is working fine with a width of 256 (2**4 * 16), why do you want 
to change it to have a smaller focus region ?

> 
> Signed-off-by: Kate Hsuan <hpa at redhat.com>
> ---
> The kernel patch is shown as following URL.
> https://lore.kernel.org/linux-media/CAEth8oES8abPO4p7eFv43PwDXuxeOmg1661YtVvykBPrkagzKg@mail.gmail.com/T/#mb02fa73ce9e3089a4619c318badb2047a3ac39e2
> ---
>   src/ipa/ipu3/algorithms/af.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/ipa/ipu3/algorithms/af.h b/src/ipa/ipu3/algorithms/af.h
> index 13c7e0e8..108fcd18 100644
> --- a/src/ipa/ipu3/algorithms/af.h
> +++ b/src/ipa/ipu3/algorithms/af.h
> @@ -20,7 +20,7 @@ static constexpr uint8_t kAfMinGridWidth = 16;
>   static constexpr uint8_t kAfMinGridHeight = 16;
>   static constexpr uint8_t kAfMaxGridWidth = 32;
>   static constexpr uint8_t kAfMaxGridHeight = 24;
> -static constexpr uint16_t kAfMinGridBlockWidth = 4;
> +static constexpr uint16_t kAfMinGridBlockWidth = 3;
>   static constexpr uint16_t kAfMinGridBlockHeight = 3;
>   static constexpr uint16_t kAfMaxGridBlockWidth = 6;
>   static constexpr uint16_t kAfMaxGridBlockHeight = 6;