From: Takashi Iwai Date: Thu, 6 Sep 2012 12:58:00 +0000 (+0200) Subject: ALSA: usb-audio: Fix bogus error messages for delay accounting X-Git-Tag: Ubuntu-5.2.0-15.16~17289^2~4 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=1213a205f9ed27d97de3d5bed28fb085ef4853e2;p=mirror_ubuntu-eoan-kernel.git 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 Cc: [v3.5+] Signed-off-by: Takashi Iwai --- 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 */