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| author | Takashi Iwai <tiwai@suse.de> | 2012-11-23 16:00:37 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2012-11-23 16:07:11 +0100 |
| commit | 48779a0b8ffc45f7f2b519ef462a72b1c5208d09 (patch) | |
| tree | 4ba2b63bfe9d922a6fd6d5c6d9558f4fd2f28981 /sound/usb | |
| parent | 3f94fad09538ec988919ec3f371841182df71d04 (diff) | |
| download | linux-48779a0b8ffc45f7f2b519ef462a72b1c5208d09.tar.gz linux-48779a0b8ffc45f7f2b519ef462a72b1c5208d09.tar.bz2 linux-48779a0b8ffc45f7f2b519ef462a72b1c5208d09.zip | |
ALSA: usb-audio: fix delay account during pause
When a playback stream is paused, the stream isn't actually stopped,
thus we still need to take care of the in-flight data amount for the
delay calculation. Otherwise the value of subs->last_delay is no
longer reliable and can give a bogus value after resuming from pause.
This will result in "delay: estimated XX, actual YY" error messages.
Also, during pause after all in flight data are processed
(i.e. last_delay = 0), we don't have to calculate the actual delay
from the current frame. Give a short path in such a case.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
| -rw-r--r-- | sound/usb/pcm.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 8e1d5e00c182..7c64b9560b18 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -46,6 +46,9 @@ snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs, int frame_diff; int est_delay; + if (!subs->last_delay) + return 0; /* short path */ + current_frame_number = usb_get_current_frame_number(subs->dev); /* * HCD implementations use different widths, use lower 8 bits. @@ -1195,6 +1198,9 @@ static void retire_playback_urb(struct snd_usb_substream *subs, return; spin_lock_irqsave(&subs->lock, flags); + if (!subs->last_delay) + goto out; /* short path */ + est_delay = snd_usb_pcm_delay(subs, runtime->rate); /* update delay with exact number of samples played */ if (processed > subs->last_delay) @@ -1212,6 +1218,15 @@ static void retire_playback_urb(struct snd_usb_substream *subs, snd_printk(KERN_DEBUG "delay: estimated %d, actual %d\n", est_delay, subs->last_delay); + if (!subs->running) { + /* update last_frame_number for delay counting here since + * prepare_playback_urb won't be called during pause + */ + subs->last_frame_number = + usb_get_current_frame_number(subs->dev) & 0xff; + } + + out: spin_unlock_irqrestore(&subs->lock, flags); } @@ -1253,7 +1268,8 @@ static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substrea return 0; case SNDRV_PCM_TRIGGER_PAUSE_PUSH: subs->data_endpoint->prepare_data_urb = NULL; - subs->data_endpoint->retire_data_urb = NULL; + /* keep retire_data_urb for delay calculation */ + subs->data_endpoint->retire_data_urb = retire_playback_urb; subs->running = 0; return 0; } |