USB 2.0 ehci failure with large amount of RAM (4GB) on x86_64

["Nathan Becker" <nathanbecker@gmail.com>]

Hi,

I recently added two more memory modules to my Gigabyte K8NXP-SLI
motherboard, bringing the total up to 4GB.  I had 2GB previously and
things were running well with kernel 2.6.16.9 x86_64. The CPU is an
AMD 4800+ X2.

After the upgrade, USB 2.0 stopped working. After connecting a pen
drive the following dmesg comes up

ehci_hcd 0000:00:02.1: GetStatus port 3 status 001803 POWER sig=j CSC CONNECT
hub 1-0:1.0: port 3, status 0501, change 0001, 480 Mb/s
hub 1-0:1.0: debounce: port 3: total 100ms stable 100ms status 0x501
ehci_hcd 0000:00:02.1: port 3 high speed
ehci_hcd 0000:00:02.1: GetStatus port 3 status 001005 POWER sig=se0 PE CONNECT
usb 1-3: new high speed USB device using ehci_hcd and address 4
usb 1-3: khubd timed out on ep0in len=0/64
usb 1-3: khubd timed out on ep0in len=0/64
usb 1-3: khubd timed out on ep0in len=0/64

and then it repeats attempting different addresses.  If I rmmod
ehci_hcd, then I can get the device to work, of course it's just
running at USB  1.1.

There appear to be varying reports of this problem in bugzilla and on
message boards:
bugzilla #5835
bugzilla #6201

 I am not sure which of these, if any, are the same as the problem I'm
having.  Any advice on where to go with this problem would be much
appreciated.  I suspect that a significant clue to this is that it
only occurs with large amounts of RAM. It also only seems to occur in
64-bit mode.  I booted a 32-bit kernel from the Slax live CD  5.1.0
and USB 2.0 worked fine with all my RAM intact (well only 3.4 GB, but
that's a different story). I'm happy to post more details and or try
patches out.  I just retested with kernel  2.6.16.13 and the problem
persists.

I've already tried various combinations of  settings in the BIOS, but
they have no effect.  There is an option to remap for 4GB.  If that is
turned off then the kernel only sees  3.4 GB of RAM instead of 4GB,
but it seems to have no effect on this problem.  I also tried changing
the USB memory option between shadow and lowmem.  That also had no
effect on this problem.  I do use the NVIDIA binary graphics driver,
but I retested for this problem without it loaded and the problem
persists.

Please cc me directly with any replies. Thanks very much for your help,


Nathan