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From: Leo Havm?ller on 4 Nov 2005 09:31
Hi,

Ive got a USB HID device with 2 interrupt endpoints, 64 bytes each, 1 ms
interval.

When reading, I can receive the maximum throughput of 64 KB/sec.
But when writing, I can only get to a maximum of ~32 KB/sec. USB chief shows
that the PC only issues an OUT transaction in every second frame.

IMHO the problem is that it is only possible to issue one report at the time
in the WriteFile call.
How can I queue several output reports, so a OUT transaction is issued in
every frame?

Leo Havm?ller.


From: Robert Marquardt on 5 Nov 2005 00:30
Leo Havm?ller wrote:

> IMHO the problem is that it is only possible to issue one report at the time
> in the WriteFile call.
> How can I queue several output reports, so a OUT transaction is issued in
> every frame?

Check USB IF forum. There was a question about that lately.
AFAIK you can feed it with overlapped writes.
From: Leo Havm?ller on 7 Nov 2005 02:25
> Check USB IF forum. There was a question about that lately.
> AFAIK you can feed it with overlapped writes.

Thank you, ive got it working now.
The trick is to issue multiple overlapped writes simultaneously from the
write thread.

Leo Havm?ller.


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