I've got an Dell M6500 with 12.04 installed that has its USB system randomly stopping - I can't find yet an specific behavior that would trigger the failure. From the basic lsusb before/after (below) it seems that any ports served by the M6500's docking station is failing - although the bluetooth mouse dongle is actually attached to the laptop, not the docking station. So in sum, the laptop's keyboard and touchpad still work, while anything externally connected - eg. USB keyboard and mouse - stop working.
I know it is not much information but here is the basic lsusb output before and after. Let me know what else I can provide to help find the issue.
Before (when working)
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 0c45:63fa Microdia Bus 001 Device 004: ID 0a5c:5801 Broadcom Corp. BCM5880 Secure Applications Processor with fingerprint swipe sensor Bus 001 Device 005: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0 Hub (part of BCM2046 Bluetooth) Bus 002 Device 003: ID 046d:c526 Logitech, Inc. Nano Receiver Bus 002 Device 004: ID 05ac:12a0 Apple, Inc. Bus 002 Device 005: ID 413c:2513 Dell Computer Corp. internal USB Hub of E-Port Replicator Bus 002 Device 006: ID 413c:2513 Dell Computer Corp. internal USB Hub of E-Port Replicator Bus 001 Device 006: ID 413c:8161 Dell Computer Corp. Integrated Keyboard Bus 001 Device 007: ID 413c:8162 Dell Computer Corp. Integrated Touchpad [Synaptics] Bus 002 Device 007: ID 413c:2003 Dell Computer Corp. Keyboard Bus 002 Device 008: ID 0d8c:0001 C-Media Electronics, Inc. Audio Device Bus 001 Device 008: ID 413c:8160 Dell Computer Corp. Wireless 365 Bluetooth
After (when not working)
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 0c45:63fa Microdia Bus 001 Device 004: ID 0a5c:5801 Broadcom Corp. BCM5880 Secure Applications Processor with fingerprint swipe sensor Bus 001 Device 005: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0 Hub (part of BCM2046 Bluetooth) Bus 001 Device 006: ID 413c:8161 Dell Computer Corp. Integrated Keyboard Bus 001 Device 007: ID 413c:8162 Dell Computer Corp. Integrated Touchpad [Synaptics] Bus 001 Device 008: ID 413c:8160 Dell Computer Corp. Wireless 365 Bluetooth
