On Mon, 23 Jan 2006, Arsene Hanssens wrote:
> Hi,
>
> I don't know who I'm supposed to contact but I think I found a problem
> somewhere in the kernel 2.4.31.
> Let me explain why. I was writing a USB 2.0 driver for a asynchronous
> scanner, i.e, paper can be fed through the scanner at any time (similar to
> a lottery scanner or ATM). This scanner, developed by PDI, has three bulk
> endpoints and no interrupt endpoint. One endpoint is for sending commands,
> such as DPI, color, .... One other endpoint is used to retrieve the image
> data as soon is the image is fed through the scanner while the other
> endpoint while the other endpoint is used by the scanner to send any other
> significant data. The scanner driver I developed was initially developed on
> the kernel 2.6.11 and everything functioned properly. However, when one of
> the company's customer indicated that they need this driver to work on
> Slackware 10.2 with kernel 2.4.31, I had to port this driver for that
> kernel. The driver is ported and works properly in normal circumstances.
> However, when I remove the USB cable from the scanner, it is impossible to
> reconnect to that scanner until the next reboot. Naturally, I thought that
> I had a bug in the driver and I started investigating. I found that kernel
> was looping forever in the following module:
>
> static void ehci_free_config (struct usb_hcd *hcd, struct usb_device
> *udev)
> and more specifically in
>
>
> f (qh->qh_state == QH_STATE_LINKED)
> art_unlink_async (ehci, qh);
> while (qh->qh_state != QH_STATE_IDLE
> && ehci->hcd.state != USB_STATE_HALT) {
> spin_unlock_irqrestore (&ehci->lock, flags);
> wait_ms (1);
> spin_lock_irqsave (&ehci->lock, flags);
> }
>
> qh->qh_state value remains at the value 2 and
> ehci->hcd.state remains at the value 1
>
> and that is why I can never reconnect to my driver when I reconnect the USB
> cable.
If you think there's a problem in the EHCI driver, the person to contact
is the maintainer for that driver.
> I hope that you are the correct person to report this problem because
> I'm
> at a total loss on how to proceed next.
Who do you hope is the correct person? You emailed your message to
linux-usb-users. That's not a person at all, it's a mailing list.
> I know PDI wants this driver to
> work for this kernel since their customer had some special drivers
> developed for this kernel and they cannot (or will not) upgrade to the 2.6
> kernel
>
> If you are not the person I need to report this problem to, can you
> tell
> where I have to report this anomaly.
There was a patch for the 2.6 version of ehci-hcd posted recently, and it
looks like it might be relevant to the problem you're encountering. I
don't know if it will apply directly to the 2.4.31 version of the driver,
but you can try it:
http://marc.theaimsgroup.com/?l=linux-usb-devel&m=113780678524619&w=2
Alan Stern
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