[PATCH v7 1/8] drm/display/dsc: Add flatness and initial scale value calculations

[Marijn Suijten]

On 2023-05-09 15:06:47, 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: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>

This ordering is odd: Jessica originally sent the patch, then Dmitry
seems to have sent it as part of his series and added his s-o-b [1], but
now Jessica is sending her original patch again but with Dmitry's
sign-off first.

[1]: https://lore.kernel.org/linux-arm-msm/20230403092313.235320-11-dmitry.baryshkov@linaro.org/

> ---
>  include/drm/display/drm_dsc_helper.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/include/drm/display/drm_dsc_helper.h b/include/drm/display/drm_dsc_helper.h
> index 0bb0c3afd740..422135a33d65 100644
> --- a/include/drm/display/drm_dsc_helper.h
> +++ b/include/drm/display/drm_dsc_helper.h
> @@ -25,5 +25,16 @@ void drm_dsc_set_rc_buf_thresh(struct drm_dsc_config *vdsc_cfg);
>  int drm_dsc_setup_rc_params(struct drm_dsc_config *vdsc_cfg, enum drm_dsc_params_kind kind);
>  int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg);
>  
> +static inline void drm_dsc_set_initial_scale_value(struct drm_dsc_config *dsc)

Nit: the other functions are not static inline, and are called "compute"
or "setup" (or "calculate" below) for maths.

The math itself is:

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

> +{
> +	dsc->initial_scale_value = 8 * dsc->rc_model_size /
> +		(dsc->rc_model_size - dsc->initial_offset);
> +}
> +
> +static inline int drm_dsc_calculate_flatness_det_thresh(struct drm_dsc_config *dsc)
> +{
> +	return 2 << (dsc->bits_per_component - 8);
> +}
> +
>  #endif /* _DRM_DSC_HELPER_H_ */
>  
> 
> -- 
> 2.40.1
>