[PATCH v3] drm/amd/display: fix PSR-SU/DSC interoperability support

[Hamza Mahfooz]

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 at amd.com>
---
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.
---
 .../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..381f708ef756 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 (!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 ||
+	    !(link->connector_signal & SIGNAL_TYPE_EDP) ||
+	    !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_ */
-- 
2.38.1