Please Help me with a Linux Mystery

[Kent Borg]

On Sat, Apr 15, 2006 at 04:20:01AM -0400, dsr at tao.merseine.nu wrote:
> The second item implies that you have a USB 1.0 UHCI or OHCI driver for
> the local chipset, but not a working 2.0 EHCI driver; the Knoppix disk
> has that driver and is enabling 2.0 functionality. Try hand-loading that
> module, and if it fails, that should give you a clue or two.

The module didn't say anything interesting, but I did some more
googling and saw
http://linux.derkeiler.com/Mailing-Lists/Fedora/2005-04/4365.html.
That posting suggests "sudo modprobe -r ehci_hcd", and presto!, the
disk is seen and I can mount it.  An lsmod and ehci_hcd is not there,
it has not been reloaded.

Looking on a sister server (very nearly the same hardware, almost
identical OS install) and the drive is seen and ehci_hcd is happily
loaded.

More Googling and I see http://www.gossamer-threads.com/lists/linux/kernel/553985

Looks like a hardware bug.  I also upgraded my RAM to 3GB recently and
it seems my chipset has problems doing DMA to some addresses and the
rmmod is a work-around.  I am sending an e-mail to the original poster
and see if he found a solution.  I suspect I get a PCI USB 2.0 card...

> > Mystery #2: What is the list of files Samba looks at

I haven't chased that yet.


Thanks a bunch.  Your mention of ehci_hcd helped me find it.


-kb