Re: [HANG] Trouble with NEC-based USB adapter in PCMCIA slot onE7110

From: Alan Stern
Date: Fri Aug 09 2013 - 15:35:11 EST


On Fri, 9 Aug 2013, Thomas Richter wrote:

> On 09.08.2013 19:46, Alan Stern wrote:
> > On Fri, 9 Aug 2013, Thomas Richter wrote:
> >
> >> Hi Alan, hi Dominik,
> >>
> >> maybe you want me to help out a bit - I'm having trouble getting a
> >> Delock PCMCIA to USB-2 adapter to work under linux, with strange
> >> behavior in some situations. The trouble is that while I can *read* via
> >> fast (usb 2.0) transfers from the port, an ehci-triggered write just
> >> locks up (it does not Oops, though) and I'm pretty much stuck narrowing
> >> down the problem.
> >
> > The best way to start will be to enable CONFIG_USB_DEBUG in your kernel
> > and post the dmesg log. Also post a usbmon trace showing what happens
> > when you try to write something.
>
> Will try and report back, thanks. I've bisected it down in the meantime
> to a change from 2.6.31.6 to 2.6.32.6. Interestingly, this is very much
> the same time when the udev userland changed. It works with 2.6.31.6 old
> udev, but not with 2.6.36.2, new udev.

Can't you use the new udev with the old kernel?

> Probably the handover from full speed to USB 2.0 got broken?

The handover goes the other way, from EHCI to OHCI.

> Note that this laptop has now both uhci (legacy) and ohci (as by the
> pcmcia card, as companion of the ehci) chips, which probably adds to the
> problem.

That should not make any difference.

Alan Stern

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