Jiada Wang wrote:
> since commit 57e6dae1087b ("ALSA: usb-audio: do not trust too-big
> wMaxPacketSize values"), the expected packetsize is always limited
> to nominal + 25%. It was discovered, that some devicesAndroid audio accessory > have a much > higher jitter in used packetsizes than 25% which would result in BABBLE > condition and dropping of packets. > A better solution is so assume the jitter to be the nominal packetsize: > -one nearly empty packet followed by a almost 150% sized one. > > V2: changed to assume max frequency is +50 of nominal packetsize. > > Signed-off-by: Andreas Pape <ap...@de.adit-jv.com> > Signed-off-by: Jiada Wang <jiada_w...@mentor.com> Acked-by: Clemens Ladisch <clem...@ladisch.de> > --- a/sound/usb/endpoint.c > +++ b/sound/usb/endpoint.c > @@ -632,8 +632,8 @@ 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; > > - /* assume max. frequency is 25% higher than nominal */ > - ep->freqmax = ep->freqn + (ep->freqn >> 2); > + /* assume max. frequency is 50% higher than nominal */ > + ep->freqmax = ep->freqn + (ep->freqn >> 1); > /* Round up freqmax to nearest integer in order to calculate maximum > * packet size, which must represent a whole number of frames. > * This is accomplished by adding 0x0.ffff before converting the
