linux-kernel - Re: [PATCH v4] drm/amd/display: fix PSR-SU/DSC interoperability support

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Message-ID: <35692927-8c48-20d2-589d-2fbff75c9e51@amd.com>
Date:   Fri, 6 Jan 2023 10:06:18 -0500
From:   Harry Wentland <harry.wentland@....com>
To:     Hamza Mahfooz <hamza.mahfooz@....com>,
        amd-gfx@...ts.freedesktop.org
Cc:     Leo Li <sunpeng.li@....com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Anthony Koo <Anthony.Koo@....com>,
        David Zhang <dingchen.zhang@....com>,
        Alex Hung <alex.hung@....com>, Shirish S <shirish.s@....com>,
        Po Ting Chen <robin.chen@....com>,
        Nicholas Kazlauskas <nicholas.kazlauskas@....com>,
        Brian Chang <Brian.Chang@....com>,
        Robin Chen <po-tchen@....com>,
        Tom Chung <chiahsuan.chung@....com>,
        Camille Cho <Camille.Cho@....com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] drm/amd/display: fix PSR-SU/DSC interoperability
 support



On 1/5/23 17:23, 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@....com>

Acked-by: Harry Wentland <harry.wentland@....com>

Would be good if you can get Leo's review.

Harry

> ---
> v2: move code to modules/power.
> v3: use ASSERT() instead of WARN() and add a condition that clarifies
>     that PSR-SU + DSC can only be enabled on an eDP connection.
> v4: change the logic again to allow non-eDP links to pass the first
>     filter in psr_su_set_y_granularity() (this allows us to maintain
>     the v1/v2 behaviour, while still being clear as to the fact that we
>     only care about eDP connections).
> ---
>  .../drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c |  3 ++
>  .../amd/display/modules/power/power_helpers.c | 31 +++++++++++++++++++
>  .../amd/display/modules/power/power_helpers.h |  3 ++
>  3 files changed, 37 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..cf4fa87c7db6 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 +916,34 @@ 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 ((link->connector_signal & SIGNAL_TYPE_EDP) &&
> +	    (!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))
> +		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)) {
> +			ASSERT(0);
> +			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_ */