This is a note to let you know that I've just added the patch titled
ALSA: usb-audio: Fix implicit sync clearance at stopping stream
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-usb-audio-fix-implicit-sync-clearance-at-stopping-stream.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 988cc17552606be67a956cf8cd6ff504cfc5d643 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Mon, 26 Apr 2021 08:33:49 +0200
Subject: ALSA: usb-audio: Fix implicit sync clearance at stopping stream
From: Takashi Iwai <tiwai@xxxxxxx>
commit 988cc17552606be67a956cf8cd6ff504cfc5d643 upstream.
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: Lucas Endres <jaffa225man@xxxxxxxxx>
Fixes: bf6313a0ff76 ("ALSA: usb-audio: Refactor endpoint management")
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210426063349.18601-1-tiwai@xxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/usb/endpoint.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -1442,11 +1442,11 @@ void snd_usb_endpoint_stop(struct snd_us
if (snd_BUG_ON(!atomic_read(&ep->running)))
return;
- 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);
+ }
}
/**
Patches currently in stable-queue which might be from tiwai@xxxxxxx are
queue-5.11/alsa-usb-audio-fix-implicit-sync-clearance-at-stopping-stream.patch
queue-5.11/alsa-usb-audio-add-midi-quirk-for-vox-tonelab-ex.patch
