>I am running kernel 2.4.3-12.
>I am attempting to establish USB communications to a device.
>
>Currently I am able to do send and receive control messages
>(usb_control_msg <using usb_sndctrlpipe(dev,0) and usb_rcvctrlpipe(dev,0>)
>and I am able to send bulk messages (usb_bulk_msg <using usb_sndbulkpipe(
>dev, 1)>).
Two problems were found.
The first problem was in the example of 'copy_from_user' I had looked at
there was no error checking (not a good thing). When error checking was
added, problems were found, corrected, and the correct data was then
transferred in bulk messages. Yet another example of the fact that if an
error code/condition/status is returned it should be checked and _not_
ignored.
The second problem (discovered with help from the good people at LSS), was
that -EPIPE can be returned on a usb_bulk_msg receiving on a
usb_rcvbulkpipe when fewer bytes are specified (in the usb_bulk_msg
function call) to be retrieved than what were actually received from the
device. In my case the device was always sending back a complete full
frame even though there was only one byte of data.
Between the resolution of these two problems the driver now works.
Dan
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