On Sat, Oct 13, 2001 at 12:55:41AM +0200, Martin Diehl wrote:
> On Thu, 11 Oct 2001, Jean Tourrilhes wrote:
>
> > The good news is that your code works beautifully on my box
> > for usb-ohci and usb-uhci. So, it will go out in the next rev os the
> > driver (I also want to try with an XNTD dongle).
>
> Fine, thanks. Chances are this might be interesting for Greg too, IMHO it
> is exactly this part of code which was duplicated for USB ir-serial ;-)
>
> > The bad news is that it didn't change anything with respect to
> > uhci. Same problem, same crash at the same place.
>
> Ok - lets look for another reason. Rereading your logs makes me thinking,
> the real problem is one step earlier: while usb_set_configuration()
> succeeds in irda_usb_probe() the following usb_set_interface() apparently
> returns EPIPE already.
>
> Did a short test using the ACT-IR2000U with 2.4.12-vanilla. Testbox is UP
> with SMP kernel and has Intel 82371AB rev 01 USB-UHCI controller.
> Works for me with _both_ usb-uhci and uhci - no Oops. However,
> usb_set_interface() returns -EPIPE for both! But the dongle seems to work
> nevertheless. Additionally, usb-uhci logs a status=3 error message from
> uhci_interrupt().
>
> Well, what follows is just speculation, but let's see:
>
> - uhci-status=3 in interrupt means there was a TD processing error.
> - from our former success with finding the USB-IrDA class descriptor
> interleaved with the standard descriptors we know, the device appends
> it when some standard descriptor was requested.
> - if a TD was scheduled to get a single well-known standard descriptor
> with known length, the requested transfer length was probably shorter
> than what was returned by the device with the class descriptor appended.
> - This would be detected as a BABBLE error by UHCI controller and the EP
> gets stalled. (Same with DATAOVERRUN condition for OHCI, btw.)
> - IIRC there was an issue with VIA handling of BABBLE. Probably usb-uhci
> has some fix to work around this.
> - The rest of what you see is just a consequence of this, probably with
> some racy help from SMP...
>
> What remains unclear to me is why this would happen at
> usb_set_interface() - I don't see any descriptor reading at this point.
> Seems to deserve some harder debugging.
>
> Comments?
>
> Martin
Martin : could you take over the maintainance of irda-usb ?
You are doing a great job, much better that I would do myself, so I
trust you entirely.
Moreover, I'm chasing SMP bugs in the Aironet 802.11 drivers,
so I can't be everywhere at the same time...
Have fun...
Jean
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