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[ALSA] usb-audio: actually schedule playback URBs at frame boundaries 

USB generic driver
Change prepare_playback_urb() not to stop preparing packets before a
frame boundary has been reached.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
This commit is contained in:
Clemens Ladisch 2005-08-15 08:25:24 +02:00 committed by Jaroslav Kysela
parent 7efd8bc800
commit 9624ea812c
1 changed files with 7 additions and 1 deletions
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8
sound/usb/usbaudio.c
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@ -164,6 +164,7 @@ struct snd_usb_substream {
unsigned int curframesize; /* current packet size in frames (for capture) */
unsigned int fill_max: 1; /* fill max packet size always */
unsigned int fmt_type; /* USB audio format type (1-3) */
unsigned int packs_per_ms; /* packets per millisecond (for playback) */
unsigned int running: 1; /* running status */
@ -537,9 +538,13 @@ static int prepare_playback_urb(snd_usb_substream_t *subs,
urb->iso_frame_desc[i].length = 0;
urb->number_of_packets++;
}
break;
}
break;
}
/* finish at the frame boundary at/after the period boundary */
if (period_elapsed &&
(i & (subs->packs_per_ms - 1)) == subs->packs_per_ms - 1)
break;
}
if (subs->hwptr_done + offs > runtime->buffer_size) {
/* err, the transferred area goes over buffer boundary. */
@ -907,6 +912,7 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
packs_per_ms = 8 >> subs->datainterval;
else
packs_per_ms = 1;
subs->packs_per_ms = packs_per_ms;
if (is_playback) {
urb_packs = nrpacks;