diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 5af16ca4dabd..71f7fba2c9e2 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5145,12 +5145,15 @@ skl_allocate_plane_ddb(struct skl_plane_ddb_iter *iter,
 		       const struct skl_wm_level *wm,
 		       u64 data_rate)
 {
-	u16 extra;
+	u16 extra = 0;
 
-	extra = min_t(u16, iter->size,
-		      DIV64_U64_ROUND_UP(iter->size * data_rate, iter->data_rate));
-	iter->size -= extra;
-	iter->data_rate -= data_rate;
+	if (data_rate) {
+		extra = min_t(u16, iter->size,
+			      DIV64_U64_ROUND_UP(iter->size * data_rate,
+						 iter->data_rate));
+		iter->size -= extra;
+		iter->data_rate -= data_rate;
+	}
 
 	return wm->min_ddb_alloc + extra;
 }
@@ -5193,9 +5196,6 @@ skl_crtc_allocate_plane_ddb(struct intel_atomic_state *state,
 	skl_ddb_entry_init(&crtc_state->wm.skl.plane_ddb_y[PLANE_CURSOR],
 			   alloc->end - iter.total[PLANE_CURSOR], alloc->end);
 
-	if (iter.data_rate == 0)
-		return 0;
-
 	/*
 	 * Find the highest watermark level for which we can satisfy the block
 	 * requirement of active planes.
@@ -5234,6 +5234,10 @@ skl_crtc_allocate_plane_ddb(struct intel_atomic_state *state,
 		return -EINVAL;
 	}
 
+	/* avoid the WARN later when we don't allocate any extra DDB */
+	if (iter.data_rate == 0)
+		iter.size = 0;
+
 	/*
 	 * Grant each plane the blocks it requires at the highest achievable
 	 * watermark level, plus an extra share of the leftover blocks
@@ -5246,20 +5250,10 @@ skl_crtc_allocate_plane_ddb(struct intel_atomic_state *state,
 		if (plane_id == PLANE_CURSOR)
 			continue;
 
-		/*
-		 * We've accounted for all active planes; remaining planes are
-		 * all disabled.
-		 */
-		if (iter.data_rate == 0)
-			break;
-
 		iter.total[plane_id] =
 			skl_allocate_plane_ddb(&iter, &wm->wm[level],
 					       crtc_state->plane_data_rate[plane_id]);
 
-		if (iter.data_rate == 0)
-			break;
-
 		iter.uv_total[plane_id] =
 			skl_allocate_plane_ddb(&iter, &wm->uv_wm[level],
 					       crtc_state->uv_plane_data_rate[plane_id]);