Once the isochronous operation has been initialized, you may
start and stop packet transmission with
raw1394_iso_xmit/recv_start() and
raw1394_iso_stop(). It is legal to call
these as many times as you want, and it is permissible to
start an already-started stream or stop an already-stopped
stream. Packets that have been queued for transmission or
reception will remain queued when the operation is stopped.
raw1394_iso_xmit/recv_start() allow you
to specify on which isochronous cycle number to start
transmitting or receiving packets. Pass -1 to start
immediately. This parameter is ignored if isochronous
transmission or reception is already in progress.
raw1394_iso_xmit_start() has an
additional parameter, prebuffer_packets,
which specifies how many packets to queue up before starting
transmission. Possible values range from zero (start
transmission immediately after the first packet is queued)
up to the total number of packets in the buffer.
Once the isochronous operation has started, you must
repeatedly call raw1394_loop_iterate()
as usual to drive packet processing.