Re: [PATCH v2] drm/amd/display: fix PSR-SU/DSC interoperability support

[Harry Wentland <harry.wentland@amd.com>]

On 1/5/23 12:38, Hamza Mahfooz wrote:
> Currently, there are issues with enabling PSR-SU + DSC. This stems from
> the fact that DSC imposes a slice height on transmitted video data and
> we are not conforming to that slice height in PSR-SU regions. So, pass
> slice_height into su_y_granularity to feed the DSC slice height into
> PSR-SU code.
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> ---
> v2: move code to modules/power.
> ---
>  .../drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c |  3 ++
>  .../amd/display/modules/power/power_helpers.c | 35 +++++++++++++++++++
>  .../amd/display/modules/power/power_helpers.h |  3 ++
>  3 files changed, 41 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
> index 26291db0a3cf..872d06fe1436 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
> @@ -122,6 +122,9 @@ bool amdgpu_dm_link_setup_psr(struct dc_stream_state *stream)
>  		psr_config.allow_multi_disp_optimizations =
>  			(amdgpu_dc_feature_mask & DC_PSR_ALLOW_MULTI_DISP_OPT);
>  
> +		if (!psr_su_set_y_granularity(dc, link, stream, &psr_config))
> +			return false;
> +
>  		ret = dc_link_setup_psr(link, stream, &psr_config, &psr_context);
>  
>  	}
> diff --git a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
> index 9b5d9b2c9a6a..4d27ad9f7370 100644
> --- a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
> +++ b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
> @@ -916,3 +916,38 @@ bool mod_power_only_edp(const struct dc_state *context, const struct dc_stream_s
>  {
>  	return context && context->stream_count == 1 && dc_is_embedded_signal(stream->signal);
>  }
> +
> +bool psr_su_set_y_granularity(struct dc *dc, struct dc_link *link,
> +			      struct dc_stream_state *stream,
> +			      struct psr_config *config)
> +{
> +	uint16_t pic_height;
> +	uint8_t slice_height;
> +
> +	if (!dc->caps.edp_dsc_support ||
> +	    link->panel_config.dsc.disable_dsc_edp ||
> +	    !link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_SUPPORT ||
> +	    !stream->timing.dsc_cfg.num_slices_v)

I'm not sure this condition is correct. We can have DSC but not eDP DSC
support.

> +		return true;
> +
> +	pic_height = stream->timing.v_addressable +
> +		stream->timing.v_border_top + stream->timing.v_border_bottom;
> +	slice_height = pic_height / stream->timing.dsc_cfg.num_slices_v;
> +
> +	if (slice_height) {
> +		if (config->su_y_granularity &&
> +		    (slice_height % config->su_y_granularity)) {
> +			WARN(1,

We don't use WARN in display/dc or display/modules. DC_LOG_WARNING
might be better, or log it in the caller.

Harry

> +			     "%s: dsc: %d, slice_height: %d, num_slices_v: %d\n",
> +			     __func__,
> +			     stream->sink->dsc_caps.dsc_dec_caps.is_dsc_supported,
> +			     slice_height,
> +			     stream->timing.dsc_cfg.num_slices_v);
> +			return false;
> +		}
> +
> +		config->su_y_granularity = slice_height;
> +	}
> +
> +	return true;
> +}
> diff --git a/drivers/gpu/drm/amd/display/modules/power/power_helpers.h b/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
> index 316452e9dbc9..bb16b37b83da 100644
> --- a/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
> +++ b/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
> @@ -59,4 +59,7 @@ void mod_power_calc_psr_configs(struct psr_config *psr_config,
>  		const struct dc_stream_state *stream);
>  bool mod_power_only_edp(const struct dc_state *context,
>  		const struct dc_stream_state *stream);
> +bool psr_su_set_y_granularity(struct dc *dc, struct dc_link *link,
> +			      struct dc_stream_state *stream,
> +			      struct psr_config *config);
>  #endif /* MODULES_POWER_POWER_HELPERS_H_ */