diff options
Diffstat (limited to 'sound/usb')
| -rw-r--r-- | sound/usb/usbaudio.c | 34 |
1 files changed, 14 insertions, 20 deletions
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index d5013383fad..f5aadb00198 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -475,6 +475,18 @@ static int retire_playback_sync_urb_hs(struct snd_usb_substream *subs, return 0; } +/* determine the number of frames in the next packet */ +static int snd_usb_audio_next_packet_size(struct snd_usb_substream *subs) +{ + if (subs->fill_max) + return subs->maxframesize; + else { + subs->phase = (subs->phase & 0xffff) + + (subs->freqm << subs->datainterval); + return min(subs->phase >> 16, subs->maxframesize); + } +} + /* * Prepare urb for streaming before playback starts. * @@ -492,16 +504,7 @@ static int prepare_startup_playback_urb(struct snd_usb_substream *subs, urb->dev = ctx->subs->dev; urb->number_of_packets = subs->packs_per_ms; for (i = 0; i < subs->packs_per_ms; ++i) { - /* calculate the size of a packet */ - if (subs->fill_max) - counts = subs->maxframesize; /* fixed */ - else { - subs->phase = (subs->phase & 0xffff) - + (subs->freqm << subs->datainterval); - counts = subs->phase >> 16; - if (counts > subs->maxframesize) - counts = subs->maxframesize; - } + counts = snd_usb_audio_next_packet_size(subs); urb->iso_frame_desc[i].offset = offs * stride; urb->iso_frame_desc[i].length = counts * stride; offs += counts; @@ -538,16 +541,7 @@ static int prepare_playback_urb(struct snd_usb_substream *subs, urb->number_of_packets = 0; spin_lock_irqsave(&subs->lock, flags); for (i = 0; i < ctx->packets; i++) { - /* calculate the size of a packet */ - if (subs->fill_max) - counts = subs->maxframesize; /* fixed */ - else { - subs->phase = (subs->phase & 0xffff) - + (subs->freqm << subs->datainterval); - counts = subs->phase >> 16; - if (counts > subs->maxframesize) - counts = subs->maxframesize; - } + counts = snd_usb_audio_next_packet_size(subs); /* set up descriptor */ urb->iso_frame_desc[i].offset = offs * stride; urb->iso_frame_desc[i].length = counts * stride; |