read(2) always returns 0 when reading from /dev/usb/n.m.k bulk IN endpoint

Peer Stritzinger peerst at gmail.com
Mon Jul 12 20:41:59 UTC 2010


Hi,

On Mon, Jul 12, 2010 at 8:20 PM, Hans Petter Selasky
<hselasky at freebsd.org>wrote:

> On Monday 12 July 2010 19:22:28 Peer Stritzinger wrote:
> > However the read always returns 0.
> >
> > Tried different buffer sizes etc.
> Hi,
>
> Maybe you are missing to set the short transfer OK flag.
>
> Else I recommend using LibUSB.
>
> --HPS
>

Did'nt set this flag (not doing any ioctls on the ugen device at all).

However I did try matching either the max packetlen, or the read buffer size
with the actual bytes sent, so I thought it shouldn't matter.

I'll move on to libusb and not waste any more time with the raw interfaces.

Thanks
-- Peer


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