drm/i915: Determine DRRS frontbuffer_bits ahead of time

Pre-determine the frontbuffer_bits for the each pipe during
intel_drrs_enable(). Will become useful for bigjoiner use cases
soon.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220315132752.11849-5-ville.syrjala@linux.intel.comReviewed-by: José Roberto de Souza <jose.souza@intel.com>

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1302,6 +1302,7 @@ struct intel_crtc {
 		struct mutex mutex;
 		struct delayed_work work;
 		enum drrs_refresh_rate refresh_rate;
+		unsigned int frontbuffer_bits;
 		unsigned int busy_frontbuffer_bits;
 		enum transcoder cpu_transcoder;
 		struct intel_link_m_n m_n, m2_n2;

drivers/gpu/drm/i915/display/intel_drrs.c

@@ -168,6 +168,13 @@ static void intel_drrs_set_state(struct intel_crtc *crtc,
 	crtc->drrs.refresh_rate = refresh_rate;
 }
 
+static unsigned int intel_drrs_frontbuffer_bits(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+
+	return INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+}
+
 /**
  * intel_drrs_enable - init drrs struct if supported
  * @crtc_state: A pointer to the active crtc state.
@@ -190,6 +197,7 @@ void intel_drrs_enable(const struct intel_crtc_state *crtc_state)
 	crtc->drrs.cpu_transcoder = crtc_state->cpu_transcoder;
 	crtc->drrs.m_n = crtc_state->dp_m_n;
 	crtc->drrs.m2_n2 = crtc_state->dp_m2_n2;
+	crtc->drrs.frontbuffer_bits = intel_drrs_frontbuffer_bits(crtc_state);
 	crtc->drrs.busy_frontbuffer_bits = 0;
 
 	mutex_unlock(&crtc->drrs.mutex);
@@ -216,6 +224,7 @@ void intel_drrs_disable(const struct intel_crtc_state *old_crtc_state)
 		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_HIGH);
 
 	crtc->drrs.cpu_transcoder = INVALID_TRANSCODER;
+	crtc->drrs.frontbuffer_bits = 0;
 	crtc->drrs.busy_frontbuffer_bits = 0;
 
 	mutex_unlock(&crtc->drrs.mutex);
@@ -278,7 +287,7 @@ static void intel_drrs_frontbuffer_update(struct drm_i915_private *dev_priv,
 			continue;
 		}
 
-		frontbuffer_bits = all_frontbuffer_bits & INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+		frontbuffer_bits = all_frontbuffer_bits & crtc->drrs.frontbuffer_bits;
 		if (invalidate)
 			crtc->drrs.busy_frontbuffer_bits |= frontbuffer_bits;
 		else