[Libusb-devel] Using another enpoint/pipe to send sync information?

[Nuno S. <ns...@ed...>]

Hi,

Currently i'm using isochronous transfers to constantly send 1024 bytes 
from the device to the host.

It happens that I divide the data in 4 packets of 256 bytes. This arises 
some synchronizations problems.

Because the host can start the application at any time, and device is 
always working event if the host is not listening to,
currently i'm sending a sync frame of 256 bytes composed of zeros.

I know, this is a very basic and stupid way of doing it, but it was on 
my first experiments and now I want to improve this in order
to maximize my transfer throughput.

This can at least improve in 20 percent my useful transfer rates, 
because I'm wasting a 256 byte packet of information.

So, what are my chances? I was thinking to use control endpoint to send 
a sync packet instead of a sync frame. It needed to be sent by the device
every time it reaches the last packet.

For its turn, the host needs to listen to this packet without loosing 
any of the isochronous packets.

I would love to hear your opinion about this, as well as possible 
techniques to be applied in this case. If my solution seems to be 
feasible or if it is unreal for the circumstances.

With my best regards,

Nuno