drm/amd/display: Allow DSC on supported MST branch devices

From Nicholas Kazlauskas
775191dd4c1bcf546ab7ce87f3476537615437b7 in linux 5.10.y/5.10.84
94ebc035456a4ccacfbbef60c444079a256623ad in mainline linux

1 files changed, 16 insertions, 4 deletions

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 955a055bd98..d617e98afb7 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -36,6 +36,8 @@
 #include "dm_helpers.h"
 
 #include "dc_link_ddc.h"
+#include "ddc_service_types.h"
+#include "dpcd_defs.h"
 
 #include "i2caux_interface.h"
 #if defined(CONFIG_DEBUG_FS)
@@ -152,6 +154,16 @@ static const struct drm_connector_funcs dm_dp_mst_connector_funcs = {
 };
 
 #if defined(CONFIG_DRM_AMD_DC_DCN)
+static bool needs_dsc_aux_workaround(struct dc_link *link)
+{
+	if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 &&
+	    (link->dpcd_caps.dpcd_rev.raw == DPCD_REV_14 || link->dpcd_caps.dpcd_rev.raw == DPCD_REV_12) &&
+	    link->dpcd_caps.sink_count.bits.SINK_COUNT >= 2)
+		return true;
+
+	return false;
+}
+
 static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnector)
 {
 	struct dc_sink *dc_sink = aconnector->dc_sink;
@@ -159,7 +171,7 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
 	u8 dsc_caps[16] = { 0 };
 
 	aconnector->dsc_aux = drm_dp_mst_dsc_aux_for_port(port);
-#if defined(CONFIG_HP_HOOK_WORKAROUND)
+
 	/*
 	 * drm_dp_mst_dsc_aux_for_port() will return NULL for certain configs
 	 * because it only check the dsc/fec caps of the "port variable" and not the dock
@@ -169,10 +181,10 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
 	 * Workaround: explicitly check the use case above and use the mst dock's aux as dsc_aux
 	 *
 	 */
-
-	if (!aconnector->dsc_aux && !port->parent->port_parent)
+	if (!aconnector->dsc_aux && !port->parent->port_parent &&
+	    needs_dsc_aux_workaround(aconnector->dc_link))
 		aconnector->dsc_aux = &aconnector->mst_port->dm_dp_aux.aux;
-#endif
+
 	if (!aconnector->dsc_aux)
 		return false;