USB 2.0 (EHCI) keeps crapping out (3.2.29)

[Logan Rathbone <loganrathbone@gmail.com>]

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Running vanilla 3.2.29 (Slackware 14.0).  I also had this issue on 
2.6.37.6 and *possibly* 2.6.33.x, but I don't recall.

Every now and again (could be every few days, could take a couple of 
weeks... depends.) USB 2.0 stops working.  My scanner as well as certain 
mass-storage devices that are USB-2.0 compatible fail to function all of 
a sudden.

With the said mass storage devices, I get lots of errors like this in my 
logs:

hub 1-0:1.0: unable to enumerate USB device on port 3

Devices that have previously been mounted and accessed successfully 
begin giving input/output errors when I try to ls them.

rmmod'ing ehci_hcd and modprobe'ing it again resolves the issue until it 
occurs again.

It *could* be a hardware problem, but it seems odd that unloading & 
reloading the module instantly makes it work perfectly again.

Via USB 1.1/2.0 controller from circa 2002-2003.

If anyone has any ideas, please let me know...

logan@logancomp:~$ /sbin/lspci |grep -i usb
00:10.0 USB controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 
Controller (rev 80)
00:10.1 USB controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 
Controller (rev 80)
00:10.2 USB controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 
Controller (rev 80)
00:10.3 USB controller: VIA Technologies, Inc. USB 2.0 (rev 82)

logan@logancomp:~$ cat /proc/cmdline
auto BOOT_IMAGE=Slackware ro root=802 nohz=off highres=off 
clocksource=jiffies acpi_enforce_resources=lax vt.default_utf8=0