On 08/27/2014 09:07 AM, Jassi Brar wrote: > On Wed, Aug 27, 2014 at 12:20 PM, Daniel Mack <daniel@xxxxxxxxxx> wrote: >> Hmm? The first USB_XFERS packets will only contain zeros, and we're only >> preparing those here. For every successive packet, the length is >> recalculated and the audio material is copied in accordingly before the >> requets is requeued. What buffers should overlap here? >> > For 44100/2/S16, req_len is 176 or 44 frames. But we need to send 45 > frames in a packet occasionally. > > req[0]->buf = rbuf + 0 and req[1]->buf = rbuf + 176. No. req[0]->buf = rbuf + 0 and req[1]->buf = rbuf + max_psize. prm->max_psize is still set to wMaxPacketSize of the endpoint. We just decide how much of it to really use dynamically, each time before a packet with real payload is commited. > But what if we req[0] needed to carry the packet with 45 frames? Then we do so in iso_complete(). This is unrelated to the first USB_XFERS dummy packets. I just wanted to avoid sending queuing them with max_psize length. Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
