drm/i915/display: Ensure PSR gets disabled if no encoders in new state

Currently PSR is left enabled when all planes are disabled if there
is no attached encoder in new state. This seems to be causing FIFO
underruns.

Fix this by checking if encoder exists in new crtc state and disable
PSR if it doesn't.

v2: Unify disable logic with existing

Cc: Mika Kahola <mika.kahola@intel.com>
Reported-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220711111750.881552-1-jouni.hogander@intel.com

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

@@ -1863,36 +1863,45 @@ void intel_psr_pre_plane_update(struct intel_atomic_state *state,
 				struct intel_crtc *crtc)
 {
 	struct drm_i915_private *i915 = to_i915(state->base.dev);
-	const struct intel_crtc_state *crtc_state =
-		intel_atomic_get_new_crtc_state(state, crtc);
-	struct intel_encoder *encoder;
+	struct intel_crtc_state *new_crtc_state, *old_crtc_state;
+	int i;
 
 	if (!HAS_PSR(i915))
 		return;
 
-	for_each_intel_encoder_mask_with_psr(state->base.dev, encoder,
-					     crtc_state->uapi.encoder_mask) {
-		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
-		struct intel_psr *psr = &intel_dp->psr;
-		bool needs_to_disable = false;
+	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
+					    new_crtc_state, i) {
+		struct intel_encoder *encoder;
+		u32 old_new_encoder_mask = old_crtc_state->uapi.encoder_mask |
+			new_crtc_state->uapi.encoder_mask;
 
-		mutex_lock(&psr->lock);
+		for_each_intel_encoder_mask_with_psr(state->base.dev, encoder,
+						     old_new_encoder_mask) {
+			struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+			struct intel_psr *psr = &intel_dp->psr;
+			bool needs_to_disable = false;
 
-		/*
-		 * Reasons to disable:
-		 * - PSR disabled in new state
-		 * - All planes will go inactive
-		 * - Changing between PSR versions
-		 */
-		needs_to_disable |= intel_crtc_needs_modeset(crtc_state);
-		needs_to_disable |= !crtc_state->has_psr;
-		needs_to_disable |= !crtc_state->active_planes;
-		needs_to_disable |= crtc_state->has_psr2 != psr->psr2_enabled;
+			mutex_lock(&psr->lock);
 
-		if (psr->enabled && needs_to_disable)
-			intel_psr_disable_locked(intel_dp);
+			/*
+			 * Reasons to disable:
+			 * - PSR disabled in new state
+			 * - All planes will go inactive
+			 * - Changing between PSR versions
+			 * - Encoder isn't present in new mask
+			 */
+			needs_to_disable |= intel_crtc_needs_modeset(new_crtc_state);
+			needs_to_disable |= !new_crtc_state->has_psr;
+			needs_to_disable |= !new_crtc_state->active_planes;
+			needs_to_disable |= new_crtc_state->has_psr2 != psr->psr2_enabled;
+			needs_to_disable |= !(new_crtc_state->uapi.encoder_mask &
+					      drm_encoder_mask(&(encoder)->base));
 
-		mutex_unlock(&psr->lock);
+			if (psr->enabled && needs_to_disable)
+				intel_psr_disable_locked(intel_dp);
+
+			mutex_unlock(&psr->lock);
+		}
 	}
 }