[PATCH 2/4] drm/i915/psr: Read Intel DPCD workaround register

["Jouni Högander" <jouni.hogander@intel.com>]

Read Intel DPCD workaround register and store it into
intel_connector->dp.psr_caps. Psr_caps was chosen as currently it contains
only PSR workaround for PSR2 SDP on prior scanline implementation.

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_types.h | 1 +
 drivers/gpu/drm/i915/display/intel_psr.c           | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index ee076106be85..ec00fcb46734 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -584,6 +584,7 @@ struct intel_connector {
 
 		struct {
 			u8 dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
+			u8 intel_wa_dpcd;
 
 			bool support;
 			bool su_support;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index b4ca5843d098..1f3f0d35d52a 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -44,6 +44,7 @@
 #include "intel_display_wa.h"
 #include "intel_dmc.h"
 #include "intel_dp.h"
+#include "intel_dpcd.h"
 #include "intel_dp_aux.h"
 #include "intel_dp_tunnel.h"
 #include "intel_dsb.h"
@@ -717,8 +718,13 @@ static void _psr_init_dpcd(struct intel_dp *intel_dp, struct intel_connector *co
 			    connector->dp.psr_caps.su_support ? "" : "not ");
 	}
 
-	if (connector->dp.psr_caps.su_support)
+	if (connector->dp.psr_caps.su_support) {
+		ret = drm_dp_dpcd_read_byte(&intel_dp->aux, INTEL_WA_REGISTER_CAPS,
+					    &connector->dp.psr_caps.intel_wa_dpcd);
+		if (ret < 0)
+			return;
 		_psr_compute_su_granularity(intel_dp, connector);
+	}
 }
 
 void intel_psr_init_dpcd(struct intel_dp *intel_dp, struct intel_connector *connector)
-- 
2.43.0