[PATCH v6 3/7] drm/msm/dpu: Use DRM DSC helper for det_thresh_flatness

[Marijn Suijten]

On 2023-04-12 16:25:17, Jessica Zhang wrote:
> Use the DRM DSC helper for det_thresh_flatness to match downstream
> implementation and the DSC spec.

This should put more emphasis on the fact that the helper **has a
different math implementation** to calculate the value differently, and
that this hence is a **semantic change**.  Otherwise the Fixes: won't
make sense and the reader wouldn't notice it.

> Changes in V2:
> - Added a Fixes tag
> 
> Fixes: c110cfd1753e ("drm/msm/disp/dpu1: Add support for DSC")
> Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

I've made the same change locally, so for the change itself:

Reviewed-by: Marijn Suijten <marijn.suijten at somainline.org>

> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
> index 619926da1441..b952f7d2b7f5 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
> @@ -3,6 +3,8 @@
>   * Copyright (c) 2020-2022, Linaro Limited
>   */
>  
> +#include <drm/display/drm_dsc_helper.h>
> +
>  #include "dpu_kms.h"
>  #include "dpu_hw_catalog.h"
>  #include "dpu_hwio.h"
> @@ -102,7 +104,7 @@ static void dpu_hw_dsc_config(struct dpu_hw_dsc *hw_dsc,
>  	data |= dsc->final_offset;
>  	DPU_REG_WRITE(c, DSC_DSC_OFFSET, data);
>  
> -	det_thresh_flatness = 7 + 2 * (dsc->bits_per_component - 8);
> +	det_thresh_flatness = drm_dsc_calculate_flatness_det_thresh(dsc);
>  	data = det_thresh_flatness << 10;
>  	data |= dsc->flatness_max_qp << 5;
>  	data |= dsc->flatness_min_qp;
> 
> -- 
> 2.40.0
>