[PATCH 6.1.y 1/4] drm/i915/psr: Apply Intel DPCD workaround when SDP on prior line used

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

commit 4703049f768fc1c1caac754134118bee1a3af189 upstream.

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>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260515095756.2799483-4-jouni.hogander@intel.com
(cherry picked from commit c3fe899fbeac86ea4a5ca9dd845b2cbc0da46249)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 27 +++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index e2d7c0a6802a..505c3c4251a5 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -811,6 +811,30 @@ static bool psr2_granularity_check(struct intel_dp *intel_dp,
 	return true;
 }
 
+static bool apply_scanline_indication_wa(struct intel_dp *intel_dp,
+					 struct intel_crtc_state *crtc_state)
+{
+	u8 early_scanline_support = intel_dp->intel_wa_dpcd &
+		INTEL_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_DPCD_INTEL_WA_REGISTER_CAPS_FALL_BACK_TO_PSR1:
+		crtc_state->req_psr2_sdp_prior_scanline = false;
+		return false;
+	case INTEL_DPCD_INTEL_WA_REGISTER_CAPS_PSR2_WITH_EARLY_SCANLINE:
+		return true;
+	case INTEL_DPCD_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_dp *intel_dp,
 							struct intel_crtc_state *crtc_state)
 {
@@ -832,7 +856,8 @@ 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(intel_dp, crtc_state);
 }
 
 static bool _compute_psr2_wake_times(struct intel_dp *intel_dp,
-- 
2.43.0