Alan Stern wrote:
On Tue, 11 Nov 2003, Ian R. Meinzen wrote:
Hello all,
First, a disclaimer - I am very new to driver development, so please
bear with my ignorance.
I am trying to write a device driver for a USB U401 from usbmicro.com.
The device works by sending a control packet to the device, then
receiving an interrupt packet back. I have (I think) the send portion
down pat, but I have yet to get the response URB correctly. I am trying
to receive the URB by calling usb_fill_int_urb() and then
usb_submit_urb() on the URB. I receive a -ENXIO from usb_submit_urb(),
and the urb->status found in the callback function is -ENOPIPE. I'm not
real sure what additional info I need to send, so please tell me if I
need to give more info.
You didn't say what version of Linux you're running or which host
controller driver -- my guess is 2.4.x and one of the UHCI drivers. They
return -ENXIO when you try to submit two URBs for the same interrupt
endpoint. (Note: when usb_submit_urb() returns an error code, urb->status
is meaningless.) If that's what you're doing, it shouldn't be a problem
to delay submitting each URB until after the previous one has completed.
If you want to see more information, edit the source file for your HCD to
leave DEBUG and dbg defined.
Alan Stern
Sorry, I should have put at least that in. I'm running 2.4.22 with the
usb-uhci driver. Should I get a -ENXIO on the first urb submitted,
though? I don't submit any urbs before a read/write/ioctl, and I am
getting an error on the first read, when the urb is first submitted. The
device returns an interrupt urb when it receives the the control urb.
Does the receipt urb need to be submitted BEFORE the control urb?
--
Ian R. Meinzen <[EMAIL PROTECTED]>
You know what I'd really, really like? What I'd pay MONEY for? A ZX81 with
a disc drive. I *understood* the ZX81. It was so easy to interface stuff to
it.
(alt.fan.pratchett)
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