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authorClemens Ladisch <clemens@ladisch.de>2005-08-15 08:25:24 +0200
committerJaroslav Kysela <perex@suse.cz>2005-08-30 08:45:47 +0200
commit9624ea812c7afd2e403c56366cadddb9ecfb88c6 (patch)
tree6d48ed32f35a3b1ebb1fac0021e810f57a141e0d /sound/usb
parent7efd8bc800324a967a37e8a425433468b7f06adb (diff)
[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>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/usbaudio.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 2b4f916a0a9..3f7930c0b61 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -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;