Commit 988cc175 authored by Takashi Iwai's avatar Takashi Iwai
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ALSA: usb-audio: Fix implicit sync clearance at stopping stream

The recent endpoint management change for implicit feedback mode added
a clearance of ep->sync_sink (formerly ep->sync_slave) pointer at
snd_usb_endpoint_stop() to assure no leftover for the feedback from
the already stopped capture stream.  This turned out to cause a
regression, however, when full-duplex streams were running and only a
capture was stopped.  Because of the above clearance of ep->sync_sink
pointer, no more feedback is done, hence the playback will stall.

This patch fixes the ep->sync_sink clearance to be done only after all
endpoints are released, for addressing the regression.
Reported-and-tested-by: default avatarLucas Endres <>
Fixes: bf6313a0 ("ALSA: usb-audio: Refactor endpoint management")
Cc: <>

Signed-off-by: default avatarTakashi Iwai <>
parent 316791b5
......@@ -1443,11 +1443,11 @@ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
if (snd_BUG_ON(!atomic_read(&ep->running)))
if (ep->sync_source)
WRITE_ONCE(ep->sync_source->sync_sink, NULL);
if (!atomic_dec_return(&ep->running))
if (!atomic_dec_return(&ep->running)) {
if (ep->sync_source)
WRITE_ONCE(ep->sync_source->sync_sink, NULL);
stop_urbs(ep, false);
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