Re: [PATCH] media: staging: ipu3-imgu: Initialise height_per_slice in the stripes

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Jean-Michel --- and Bingbu and Tianshu,

On Thu, Sep 16, 2021 at 07:25:04PM +0200, Jean-Michel Hautbois wrote:
> While playing with low resolutions for the grid, it appeared that
> height_per_slice is not initialised if we are not using both stripes for
> the calculations. This pattern occurs three times:
> - for the awb_fr processing block
> - for the af processing block
> - for the awb processing block
> 
> The idea of this small portion of code is to reduce complexity in
> loading the statistics, it could be done also when only one stripe is
> used. Fix it by getting this initialisation code outside of the else()
> test case.
> 
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> ---
>  drivers/staging/media/ipu3/ipu3-css-params.c | 44 ++++++++++----------
>  1 file changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/staging/media/ipu3/ipu3-css-params.c b/drivers/staging/media/ipu3/ipu3-css-params.c
> index e9d6bd9e9332..05da7dbdca78 100644
> --- a/drivers/staging/media/ipu3/ipu3-css-params.c
> +++ b/drivers/staging/media/ipu3/ipu3-css-params.c
> @@ -2428,16 +2428,16 @@ int imgu_css_cfg_acc(struct imgu_css *css, unsigned int pipe,
>  					acc->awb_fr.stripes[1].grid_cfg.width,
>  					b_w_log2);
>  		acc->awb_fr.stripes[1].grid_cfg.x_end = end;
> -
> -		/*
> -		 * To reduce complexity of debubbling and loading
> -		 * statistics fix grid_height_per_slice to 1 for both
> -		 * stripes.
> -		 */
> -		for (i = 0; i < stripes; i++)
> -			acc->awb_fr.stripes[i].grid_cfg.height_per_slice = 1;
>  	}
>  
> +	/*
> +	 * To reduce complexity of debubbling and loading
> +	 * statistics fix grid_height_per_slice to 1 for both
> +	 * stripes.
> +	 */
> +	for (i = 0; i < stripes; i++)
> +		acc->awb_fr.stripes[i].grid_cfg.height_per_slice = 1;
> +
>  	if (imgu_css_awb_fr_ops_calc(css, pipe, &acc->awb_fr))
>  		return -EINVAL;
>  
> @@ -2591,15 +2591,15 @@ int imgu_css_cfg_acc(struct imgu_css *css, unsigned int pipe,
>  			imgu_css_grid_end(acc->af.stripes[1].grid_cfg.x_start,
>  					  acc->af.stripes[1].grid_cfg.width,
>  					  b_w_log2);
> -
> -		/*
> -		 * To reduce complexity of debubbling and loading statistics
> -		 * fix grid_height_per_slice to 1 for both stripes
> -		 */
> -		for (i = 0; i < stripes; i++)
> -			acc->af.stripes[i].grid_cfg.height_per_slice = 1;
>  	}
>  
> +	/*
> +	 * To reduce complexity of debubbling and loading statistics
> +	 * fix grid_height_per_slice to 1 for both stripes
> +	 */
> +	for (i = 0; i < stripes; i++)
> +		acc->af.stripes[i].grid_cfg.height_per_slice = 1;
> +
>  	if (imgu_css_af_ops_calc(css, pipe, &acc->af))
>  		return -EINVAL;
>  
> @@ -2660,15 +2660,15 @@ int imgu_css_cfg_acc(struct imgu_css *css, unsigned int pipe,
>  			imgu_css_grid_end(acc->awb.stripes[1].grid.x_start,
>  					  acc->awb.stripes[1].grid.width,
>  					  b_w_log2);
> -
> -		/*
> -		 * To reduce complexity of debubbling and loading statistics
> -		 * fix grid_height_per_slice to 1 for both stripes
> -		 */
> -		for (i = 0; i < stripes; i++)
> -			acc->awb.stripes[i].grid.height_per_slice = 1;
>  	}
>  
> +	/*
> +	 * To reduce complexity of debubbling and loading statistics
> +	 * fix grid_height_per_slice to 1 for both stripes
> +	 */
> +	for (i = 0; i < stripes; i++)
> +		acc->awb.stripes[i].grid.height_per_slice = 1;
> +
>  	if (imgu_css_awb_ops_calc(css, pipe, &acc->awb))
>  		return -EINVAL;
>  

While it seems like a sensible idea to initialise arguments to firmware, does this have an
effect on the statistics format? If so, can the existing user space cope
with that?

Bingbu, Tianshu, any insights on this?

-- 
Kind regards,

Sakari Ailus