On Wed, 5 Apr 2006, Pete Zaitcev wrote:
> On Wed, 5 Apr 2006 14:16:39 -0400 (EDT), Alan Stern <[EMAIL PROTECTED]> wrote:
>
> > > I've put in a printk to check the error code, it's -110, and that is
> > > supposed to be ETIMEDOUT. According to ohci.h, this code is returned
> > > on TD_DEVNOTRESP.. but now, I'm out of clues.
>
> > The error is caused by a timeout on the USB bus. The device has a limited
> > time (a few microseconds) to respond to a packet; if it doesn't respond in
> > that time you get this error. There's no way to increase the time limit;
> > it's built into the hardware and is part of the USB specification.
>
> I think you're describing -71 above. The -110 means that upper layers
> were bored and unlinked the URB, which typically happens after a few
> seconds.
You'd think so... but ohci-hcd uses -110 where uhci-hcd uses -71. Here's
the relevant part of drivers/usb/host/ohci.h:
/* map OHCI TD status codes (CC) to errno values */
static const int cc_to_error [16] = {
/* No Error */ 0,
/* CRC Error */ -EILSEQ,
/* Bit Stuff */ -EPROTO,
/* Data Togg */ -EILSEQ,
/* Stall */ -EPIPE,
/* DevNotResp */ -ETIMEDOUT,
Of course, this doesn't explain why the device in question worked before
but not not. My guess is that this was a result of the move to new USB
host hardware, not the use of OHCI rather than UHCI per se.
Alan Stern
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