drm/i915: Deal with bigjoiner vs. DRRS

DRRS operates on transcoder level, so we should only poke at it from
the master crtc rather than letting every joined pipe give it
potentially conflicting input.

Signed-off-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Manasi Navare <[e-mail]>

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

···
 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);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	unsigned int frontbuffer_bits;
 
-	return INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+	frontbuffer_bits = INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+
+	for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc,
+					 crtc_state->bigjoiner_pipes)
+		frontbuffer_bits |= INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+
+	return frontbuffer_bits;
 }
 
 /**
···
 		return;
 
 	if (!crtc_state->hw.active)
+		return;
+
+	if (intel_crtc_is_bigjoiner_slave(crtc_state))
 		return;
 
 	mutex_lock(&crtc->drrs.mutex);
···
 		return;
 
 	if (!old_crtc_state->hw.active)
+		return;
+
+	if (intel_crtc_is_bigjoiner_slave(old_crtc_state))
 		return;
 
 	mutex_lock(&crtc->drrs.mutex);