[PATCH 3/4] drm/i915/psr: Apply Intel DPCD workaround when SDP on prior line used

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

There is Intel specific workaround DPCD address containing workaround for
case where SDP is on prior line. Apply this workaround according to values
in the offset.

Fixes: 61e887329e33 ("drm/i915/xelpd: Handle PSR2 SDP indication in the prior scanline")
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 36 +++++++++++++++++++++---
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 1f3f0d35d52a..341186622ed4 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1385,9 +1385,36 @@ static bool psr2_granularity_check(struct intel_crtc_state *crtc_state,
 	return true;
 }
 
-static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_dp,
-							struct intel_crtc_state *crtc_state)
+static bool apply_scanline_indication_wa(struct intel_crtc_state *crtc_state,
+					 struct intel_connector *connector)
 {
+	struct intel_dp *intel_dp = intel_attached_dp(connector);
+	u8 early_scanline_support = connector->dp.psr_caps.intel_wa_dpcd &
+		INTEL_WA_REGISTER_CAPS_PSR2_EARLYSCANLINE_SDP_SUPPORT_MASK;
+
+	if (intel_dp->edp_dpcd[0] >= DP_EDP_15)
+		return true;
+
+	switch(early_scanline_support)
+	{
+	case INTEL_WA_REGISTER_CAPS_FALL_BACK_TO_PSR1:
+		crtc_state->req_psr2_sdp_prior_scanline = false;
+		return false;
+	case INTEL_WA_REGISTER_CAPS_PSR2_WITH_EARLY_SCANLINE:
+		return true;
+	case INTEL_WA_REGISTER_CAPS_PSR2_WITHOUT_EARLY_SCANLINE:
+		crtc_state->req_psr2_sdp_prior_scanline = false;
+		return true;
+	default:
+		MISSING_CASE(early_scanline_support);
+		return false;
+	}
+}
+
+static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_crtc_state *crtc_state,
+							struct intel_connector *connector)
+{
+	struct intel_dp *intel_dp = intel_attached_dp(connector);
 	struct intel_display *display = to_intel_display(intel_dp);
 	const struct drm_display_mode *adjusted_mode = &crtc_state->uapi.adjusted_mode;
 	u32 hblank_total, hblank_ns, req_ns;
@@ -1406,7 +1433,8 @@ static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_d
 		return false;
 
 	crtc_state->req_psr2_sdp_prior_scanline = true;
-	return true;
+
+	return apply_scanline_indication_wa(crtc_state, connector);
 }
 
 static int intel_psr_entry_setup_frames(struct intel_dp *intel_dp,
@@ -1687,7 +1715,7 @@ static bool intel_sel_update_config_valid(struct intel_crtc_state *crtc_state,
 								      conn_state))
 		goto unsupported;
 
-	if (!_compute_psr2_sdp_prior_scanline_indication(intel_dp, crtc_state)) {
+	if (!_compute_psr2_sdp_prior_scanline_indication(crtc_state, connector)) {
 		drm_dbg_kms(display->drm,
 			    "Selective update not enabled, SDP indication do not fit in hblank\n");
 		goto unsupported;
-- 
2.43.0