1 files changed, 16 insertions, 3 deletions

diff --git a/sys/dev/sound/usb/uaudio.c b/sys/dev/sound/usb/uaudio.c
index 7e32b706c2d7..6ed81eef02ea 100644
--- a/sys/dev/sound/usb/uaudio.c
+++ b/sys/dev/sound/usb/uaudio.c
@@ -2078,9 +2078,22 @@ uaudio_chan_play_sync_callback(struct usb_xfer *xfer, usb_error_t error)
 		 * Use feedback value as fallback when there is no
 		 * recording channel:
 		 */
-		if (ch->priv_sc->sc_rec_chan.num_alt == 0)
-			ch->jitter_curr = temp - sample_rate;
-
+		if (ch->priv_sc->sc_rec_chan.num_alt == 0) {
+			/*
+			 * Range check the jitter values to avoid
+			 * bogus sample rate adjustments. The expected
+			 * deviation should not be more than 1Hz per
+			 * second. The USB v2.0 specification also
+			 * mandates this requirement. Refer to chapter
+			 * 5.12.4.2 about feedback.
+			 */
+			if (temp > sample_rate)
+				ch->jitter_curr = 1;
+			else if (temp < sample_rate)
+				ch->jitter_curr = -1;
+			else
+				ch->jitter_curr = 0;
+		}
 		ch->feedback_rate = temp;
 		break;