> This duplicates the read cycle timer feature of raw1394 (added in Linux
> 2.6.21) in firewire-core's userspace ABI.
Kristian and Pieter, does this simple duplication of the ioctl make
sense on its own? AFAIU rawiso's iso packet buffers look different from
fw-cdevs's. It seems to me as if rawiso always put the cycle into a user
buffer for each iso packet received...
raw1394.h::struct raw1394_iso_packet_info {
__u32 offset;
__u16 len;
__u16 cycle; /* recv only */
__u8 channel; /* recv only */
__u8 tag;
__u8 sy;
};
raw1394.c::raw1394_iso_recv_packets()
/* copy the packet_infos out */
for (i = 0; i < upackets.n_packets; i++) {
if (__copy_to_user(&upackets.infos[i],
&fi->iso_handle->infos[packet],
sizeof(struct raw1394_iso_packet_info)))
return -EFAULT;
packet = (packet + 1) % fi->iso_handle->buf_packets;
}
...while the Juju ABI returns the cycle only for those packets whose
fw_cdev_iso_packet.control had the FW_CDEV_ISO_INTERRUPT flag set.
The cycle is then written out in the fw_cdev_event_iso_interrupt event
which happens when this particular packet was received. Right?
Pieter, do applications like yours need the cycle counter only for a few
predetermined packets or for each and every packet?
--
Stefan Richter
-=====-=-=== =--= ===-=
http://arcgraph.de/sr/
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