diff options
Diffstat (limited to 'sound/usb/endpoint.c')
| -rw-r--r-- | sound/usb/endpoint.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 7a444b5501d..93e970f2b3c 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -418,6 +418,9 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep; int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK; + if (WARN_ON(!alts)) + return NULL; + mutex_lock(&chip->mutex); list_for_each_entry(ep, &chip->ep_list, list) { @@ -591,17 +594,16 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep, ep->stride = frame_bits >> 3; ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0; - /* calculate max. frequency */ - if (ep->maxpacksize) { + /* assume max. frequency is 25% higher than nominal */ + ep->freqmax = ep->freqn + (ep->freqn >> 2); + maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3)) + >> (16 - ep->datainterval); + /* but wMaxPacketSize might reduce this */ + if (ep->maxpacksize && ep->maxpacksize < maxsize) { /* whatever fits into a max. size packet */ maxsize = ep->maxpacksize; ep->freqmax = (maxsize / (frame_bits >> 3)) << (16 - ep->datainterval); - } else { - /* no max. packet size: just take 25% higher than nominal */ - ep->freqmax = ep->freqn + (ep->freqn >> 2); - maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3)) - >> (16 - ep->datainterval); } if (ep->fill_max) |