On Tue, 5 Apr 2011, gene heskett wrote: > On Tuesday, April 05, 2011 06:53:25 PM Alan Cox did opine: > > > > Because you still have the random latency of the usb involved. The > > > machine > > > > USB latency isn't random in ISO transactions, its pretty precise. > > > That has not been my experience, but that is also dated. The USB spec allows an isochronous transaction to take place at any time within the frame (or microframe) it was scheduled for. This allows a variation of up to 1 ms (or 125 us) in the tranmission times, although in practice it is usually a lot less. Also, there is a limit on how soon a new transfer can be scheduled, typically a couple of milliseconds. It's not random, but it may be a larger latency than people want. Alan Stern -- 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
