Re: USB driver problem with external hub

[Greg KH <greg@kroah.com>]

On Sat, Sep 20, 2008 at 04:35:03PM -0700, cihan öztürk wrote:
> I am working on a device driver for providing connectivity to a Silabs
> F340 board through USB. All the required software, including firmware
> on the device side, USB device driver and user level libraries as well
> as the application, are implemented. The system operates fine when
> experimental communication is considered, in which dummy data is
> simply sent and received betweeen the host and the device at Full
> speed. The trouble comes when a USB external hub is used as a gateway
> between the device and the host instead of directly connecting the USB
> cable from device to the USB port of the PC. The kernel log states
> that the transfer of urb failed due to -EPROTO(-71), which is defined
> as protocol error. I found in some resources that this error can be a
> result of (a) bitstuff error, or (b) no response packet received
> within the prescribed bus turn-around time, or (c)hardware problems
> such as bad devices (including firmware) or cables.
> The hub is a Digitus product with 7 ports and works fine with other
> USB devices such as the mouse on the same platform.
> My kernel version is 2.6.18.

Is this because you are using a USB 2.0 hub, connected via EHCI and your
device is a 1.1 speed device?  If so, this is a known issue with older
kernel versions, and has partially been fixed in newer kernel releases.

Please try 2.6.26 and let us know if that solves the issue.

Or just use a 1.1 hub, that should also work.

thanks,

greg k-h