This is required.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
---
 drivers/iommu/apple-dart.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 9c74a95eb7e819e94ab2fb47ed0d411a1eba8bf7..9c6f780dc7220096ed6bba692fa1a4bd859b0d61 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -941,6 +941,8 @@ static int apple_dart_def_domain_type(struct device *dev)
 		return IOMMU_DOMAIN_IDENTITY;
 	if (!cfg->stream_maps[0].dart->supports_bypass)
 		return IOMMU_DOMAIN_DMA;
+	if (cfg->stream_maps[0].dart->locked)
+		return IOMMU_DOMAIN_DMA;
 
 	return 0;
 }
-- 
2.48.1