[Intel-gfx] [PATCH v2 03/19] drm/i915/dp_mst: Set connector DSC capabilities and decompression AUX

Imre Deak
2023-10-10T11:24:48Z

Similarly to eDP and SST-DP connectors read out the DSC capabilities for
MST connectors as well. Atm these will match the root port's DSC caps
and only used after a follow-up change enables the decompression for
each stream separately (vs. the current way of enabling it only globally
in the first branch device downstream of the root port).

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
drivers/gpu/drm/i915/display/intel_dp.h | 3 +++
drivers/gpu/drm/i915/display/intel_dp_mst.c | 23 +++++++++++++++++++++
3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5b2b0db5c24ec..2b9af92fb8cf8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3483,8 +3483,8 @@ static void intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,
dsc_dpcd);
}

-static void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, struct intel_dp *intel_dp,
- struct intel_connector *connector)
+void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, struct intel_dp *intel_dp,
+ struct intel_connector *connector)
{
struct drm_i915_private *i915 = dp_to_i915(intel_dp);

diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 2cf3681bac64a..bd9cb9680b4cd 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -162,4 +162,7 @@ intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
bool dsc,
struct link_config_limits *limits);

+void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, struct intel_dp *intel_dp,
+ struct intel_connector *connector);
+
#endif /* __INTEL_DP_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 73e3977364632..e01f669d2c8a1 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -1126,6 +1126,21 @@ static int intel_dp_mst_add_properties(struct intel_dp *intel_dp,
return drm_connector_set_path_property(connector, pathprop);
}

+static void
+intel_dp_mst_read_decompression_port_dsc_caps(struct intel_dp *intel_dp,
+ struct intel_connector *connector)
+{
+ u8 dpcd_caps[DP_RECEIVER_CAP_SIZE];
+
+ if (!connector->dp.dsc_decompression_aux)
+ return;
+
+ if (drm_dp_read_dpcd_caps(connector->dp.dsc_decompression_aux, dpcd_caps) < 0)
+ return;
+
+ intel_dp_get_dsc_sink_cap(dpcd_caps[DP_DPCD_REV], intel_dp, connector);
+}
+
static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port,
const char *pathprop)
@@ -1159,6 +1174,14 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo

drm_connector_helper_add(connector, &intel_dp_mst_connector_helper_funcs);

+ /*
+ * TODO: set the AUX for the actual MST port decompressing the stream.
+ * At the moment the driver only supports enabling this globally in the
+ * first downstream MST branch, via intel_dp's (root port) AUX.
+ */
+ intel_connector->dp.dsc_decompression_aux = &intel_dp->aux;
+ intel_dp_mst_read_decompression_port_dsc_caps(intel_dp, intel_connector);
+
for_each_pipe(dev_priv, pipe) {
struct drm_encoder *enc =
&intel_dp->mst_encoders[pipe]->base.base;
--
2.39.2