>Date: Wed, 19 Jan 2005 15:08:11 +0100
>From: Philippe Smadja <psmadja@...>
>Subject: a question with bulk transfer.
>I have a bulk device (1 IN, 1 OUT). I would like to send a list of OUT,
>IN in a single frame (1ms)
>The USB Controller (UHCI) always waits the next frame to change the type
>I have linked the URBs (using urb->transfer_flags = USB_QUEUE_BULK).
>If I do not link the URB I have mainly the same behavior.
>Does someone have a work around ?
From: Peter Stuge <stuge-libusb@cd...> - 2005-01-20 00:17:39
On Wed, Jan 19, 2005 at 04:07:39PM +0100, Philippe Smadja wrote:
> >I have a bulk device (1 IN, 1 OUT). I would like to send a list
> >of OUT, IN in a single frame (1ms)
I'm afraid that's not possible. The USB spec only allows one
transaction per frame.
> >The USB Controller (UHCI) always waits the next frame to change
> >the type of transfer.
Right. Which is correct according to spec. You could try using high
speed and microframes, but all of that should be handled by layers
much lower than application.
Out of curiosity, what kind of device is really expecting this
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