diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 6a8f5843334e98558d09174e157c308644c736a5..956be9f7c72a44e9326bd15c3df328540747124d 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -349,7 +349,7 @@ snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor
 			 * TODO: this conversion is not complete, update it
 			 * after adding UAC3 values to asound.h
 			 */
-			switch (is->bChPurpose) {
+			switch (is->bChRelationship) {
 			case UAC3_CH_MONO:
 				map = SNDRV_CHMAP_MONO;
 				break;