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authorTakashi Iwai <tiwai@suse.de>2012-09-06 16:58:00 +0400
committerTakashi Iwai <tiwai@suse.de>2012-09-06 17:00:15 +0400
commit1213a205f9ed27d97de3d5bed28fb085ef4853e2 (patch)
treed29a9631b965cd0bf788d475f6fc563e240b48ed /sound/usb
parentab548d2dba63ba947287965e525cc02a15d9853d (diff)
downloadlinux-1213a205f9ed27d97de3d5bed28fb085ef4853e2.tar.xz
ALSA: usb-audio: Fix bogus error messages for delay accounting
The recent fix for the missing fine delayed time adjustment gives strange error messages at each start of the playback stream, such as delay: estimated 0, actual 352 delay: estimated 353, actual 705 These come from the sanity check in retire_playback_urb(). Before the stream is activated via start_endpoints(), a few silent packets have been already sent. And at this point the delay account is still in the state as if the new packets are just queued, so the driver gets confused and spews the bogus error messages. For fixing the issue, we just need to check whether the received packet is valid, whether it's zero sized or not. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: <stable@vger.kernel.org> [v3.5+] Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/pcm.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index fd5e982fc98c..f782ce19bf5a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1140,6 +1140,12 @@ static void retire_playback_urb(struct snd_usb_substream *subs,
int processed = urb->transfer_buffer_length / stride;
int est_delay;
+ /* ignore the delay accounting when procssed=0 is given, i.e.
+ * silent payloads are procssed before handling the actual data
+ */
+ if (!processed)
+ return;
+
spin_lock_irqsave(&subs->lock, flags);
est_delay = snd_usb_pcm_delay(subs, runtime->rate);
/* update delay with exact number of samples played */