On Tue, 28 Feb 2023, Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote:
> The rc_buf_thresh values are common to all DSC implementations. Move
> them to the common helper together with the code to propagage them to
> the drm_dsc_config.
>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> ---
> drivers/gpu/drm/display/drm_dsc_helper.c | 37 +++++++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_vdsc.c | 24 +--------------
> include/drm/display/drm_dsc_helper.h | 1 +
> 3 files changed, 39 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dsc_helper.c b/drivers/gpu/drm/display/drm_dsc_helper.c
> index c869c6e51e2b..ab8679c158b5 100644
> --- a/drivers/gpu/drm/display/drm_dsc_helper.c
> +++ b/drivers/gpu/drm/display/drm_dsc_helper.c
> @@ -270,6 +270,43 @@ void drm_dsc_pps_payload_pack(struct drm_dsc_picture_parameter_set *pps_payload,
> }
> EXPORT_SYMBOL(drm_dsc_pps_payload_pack);
>
> +/* From DSC_v1.11 spec, rc_parameter_Set syntax element typically constant */
> +const u16 drm_dsc_rc_buf_thresh[] = {
> + 896, 1792, 2688, 3584, 4480, 5376, 6272, 6720, 7168, 7616,
> + 7744, 7872, 8000, 8064
> +};
> +EXPORT_SYMBOL(drm_dsc_rc_buf_thresh);
This needs to be static, without exports.
> +
> +/**
> + * drm_dsc_set_rc_buf_thresh() - Set thresholds for the RC model
> + * in accordance with the DSC 1.2 specification.
> + *
> + * @vdsc_cfg: DSC Configuration data partially filled by driver
> + */
> +void drm_dsc_set_rc_buf_thresh(struct drm_dsc_config *vdsc_cfg)
> +{
> + int i = 0;
Unnecessary initialization.
> +
> + for (i = 0; i < DSC_NUM_BUF_RANGES - 1; i++) {
Please use ARRAY_SIZE(). Maybe add BUILD_BUG_ON() for DSC_NUM_BUF_RANGES
vs. ARRAY_SIZE(). (Yes, we should've used ARRAY_SIZE() in i915.)
> + /*
> + * six 0s are appended to the lsb of each threshold value
> + * internally in h/w.
> + * Only 8 bits are allowed for programming RcBufThreshold
> + */
> + vdsc_cfg->rc_buf_thresh[i] = drm_dsc_rc_buf_thresh[i] >> 6;
> + }
> +
> + /*
> + * For 6bpp, RC Buffer threshold 12 and 13 need a different value
> + * as per C Model
> + */
> + if (vdsc_cfg->bits_per_pixel == 6 << 4) {
> + vdsc_cfg->rc_buf_thresh[12] = 7936 >> 6;
> + vdsc_cfg->rc_buf_thresh[13] = 8000 >> 6;
> + }
> +}
> +EXPORT_SYMBOL(drm_dsc_set_rc_buf_thresh);
> +
> /**
> * drm_dsc_compute_rc_parameters() - Write rate control
> * parameters to the dsc configuration defined in
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index d080741fd0b3..b4faab4c8fb3 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -36,12 +36,6 @@ enum COLUMN_INDEX_BPC {
> MAX_COLUMN_INDEX
> };
>
> -/* From DSC_v1.11 spec, rc_parameter_Set syntax element typically constant */
> -static const u16 rc_buf_thresh[] = {
> - 896, 1792, 2688, 3584, 4480, 5376, 6272, 6720, 7168, 7616,
> - 7744, 7872, 8000, 8064
> -};
> -
> struct rc_parameters {
> u16 initial_xmit_delay;
> u8 first_line_bpg_offset;
> @@ -474,23 +468,7 @@ int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
> vdsc_cfg->bits_per_pixel = compressed_bpp << 4;
> vdsc_cfg->bits_per_component = pipe_config->pipe_bpp / 3;
>
> - for (i = 0; i < DSC_NUM_BUF_RANGES - 1; i++) {
> - /*
> - * six 0s are appended to the lsb of each threshold value
> - * internally in h/w.
> - * Only 8 bits are allowed for programming RcBufThreshold
> - */
> - vdsc_cfg->rc_buf_thresh[i] = rc_buf_thresh[i] >> 6;
> - }
> -
> - /*
> - * For 6bpp, RC Buffer threshold 12 and 13 need a different value
> - * as per C Model
> - */
> - if (compressed_bpp == 6) {
> - vdsc_cfg->rc_buf_thresh[12] = 0x7C;
> - vdsc_cfg->rc_buf_thresh[13] = 0x7D;
> - }
> + drm_dsc_set_rc_buf_thresh(vdsc_cfg);
>
> /*
> * From XE_LPD onwards we supports compression bpps in steps of 1
> diff --git a/include/drm/display/drm_dsc_helper.h b/include/drm/display/drm_dsc_helper.h
> index 8b41edbbabab..706ba1d34742 100644
> --- a/include/drm/display/drm_dsc_helper.h
> +++ b/include/drm/display/drm_dsc_helper.h
> @@ -14,6 +14,7 @@ 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,
> const struct drm_dsc_config *dsc_cfg);
> +void drm_dsc_set_rc_buf_thresh(struct drm_dsc_config *vdsc_cfg);
> int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg);
>
> #endif /* _DRM_DSC_HELPER_H_ */
--
Jani Nikula, Intel Open Source Graphics Center
