Re: [PATCH RFC 1/5] drm/display/dsc: Add flatness and initial scale value calculations

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 30/03/2023 02:18, Jessica Zhang wrote:
> Add helpers to calculate det_thresh_flatness and initial_scale_value as
> these calculations are defined within the DSC spec.
>
> Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
> ---
>   include/drm/display/drm_dsc_helper.h | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/include/drm/display/drm_dsc_helper.h b/include/drm/display/drm_dsc_helper.h
> index 4448c482b092..63175650a45e 100644
> --- a/include/drm/display/drm_dsc_helper.h
> +++ b/include/drm/display/drm_dsc_helper.h
> @@ -17,6 +17,16 @@ enum drm_dsc_params_kind {
>   	DRM_DSC_1_2_420,
>   };
>   
> +static inline int drm_dsc_calculate_initial_scale_value(struct drm_dsc_config *dsc)
> +{
> +	return 8 * dsc->rc_model_size / (dsc->rc_model_size - dsc->initial_offset);

Just set this in drm_dsc_config, like other functions do.

> +}
> +
> +static inline int drm_dsc_calculate_det_thresh_flatness(struct drm_dsc_config *dsc)
> +{
> +	return 2 << (dsc->bits_per_component - 8);
> +}

this is flatness_det_thresh, per the standard.

Otherwise LGTM

> +
>   void drm_dsc_dp_pps_header_init(struct dp_sdp_header *pps_header);
>   int drm_dsc_dp_rc_buffer_size(u8 rc_buffer_block_size, u8 rc_buffer_size);
>   void drm_dsc_pps_payload_pack(struct drm_dsc_picture_parameter_set *pps_sdp,

--
With best wishes
Dmitry