Weird USB lockup with Linksys USB100TX NIC

[Scott Mitchell]

So I have one of these, that I bought cheap on eBay.  It was working just
fine on my main -STABLE workstation (Abit KG7 motherboard), up until last
Friday when I moved it onto the VIA EPIA-M machine I'm building.  The NIC
was detected OK as aue0, then the machine locked up running dhclient.  It
turns out that it wasn't really hung, but apparently spinning in the kernel
on behalf of ifconfig.  I say apparently, because the only thing I could
figure out was that I had an ifconfig process consuming vast amounts of CPU
in a wait on 'usbdly', before I got fed up waiting ~20s for keypresses to
respond and rebooted.

I've since discovered that I can reproduce this on demand by booting single
user and doing an 'ifconfig down aue0'.  This will take at least a minute
to complete and leaves the machine almost totally unresponsive afterwards.
I'll often get a bunch of 'usb error on rx: IOERROR' kernel messages while
ifconfig is running.  The NIC seems to still work OK otherwise.

I get the same behaviour on the VIA and Abit boards (remember it used to
work on this one), with 4.8R, -STABLE and 5.1R.  It's tempting to assume
that the hardware has just gone bad, except that it still works on three
different Win2K machines, one of which is also my -STABLE workstation.

I know there's not much to go on, but if anyone has any idea what might
have caused this, or how to work around it, or where to start looking to
debug it myself, I'd love to hear it.  If the hardware is bad, then I'll
give it to a Windows user and move on, but it seems odd that it mostly
works, and just can't be shut down cleanly.

        Scott

-- 
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Scott Mitchell           | PGP Key ID | "Eagles may soar, but weasels
Cambridge, England       | 0x54B171B9 |  don't get sucked into jet engines"
scott at fishballoon.org | 0xAA775B8B |      -- Anon