I have a Microsoft IntelliMouse connected via USB to a computer (directly, NOT via hub) currently running Ubuntu 11.10, but this problem also existed before we upgraded from 10.10.

Every now and then (apparently randomly) the computer "pauses" for anything up to a few seconds. This usually occurs after a mouse movement and during the pause, the computer is completely unresponsive to mouse or keyboard.

lsusb shows:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0409:0058 NEC Corp. HighSpeed Hub
Bus 001 Device 004: ID 05e3:0605 Genesys Logic, Inc. USB 2.0 Hub [ednet]
Bus 003 Device 013: ID 045e:001e Microsoft Corp. IntelliMouse Explorer
Bus 001 Device 005: ID 04a9:1097 Canon, Inc. PIXMA iP5000
Bus 001 Device 006: ID 0a5c:200a Broadcom Corp. Bluetooth dongle
Bus 001 Device 007: ID 0911:1c57 Philips Speech Processing 
Bus 001 Device 008: ID 04a9:2219 Canon, Inc. CanoScan 9950F

so the mouse appears to be correctly identified.

Syslog episodically shows the following sequence:

Jan 15 11:48:32 kayes-computer kernel: [10588.512036] usb 3-1: USB disconnect, device number 10
Jan 15 11:48:33 kayes-computer kernel: [10589.248026] usb 3-1: new low speed USB device number 11 using uhci_hcd
Jan 15 11:48:33 kayes-computer mtp-probe: checking bus 3, device 11: "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-1"
Jan 15 11:48:33 kayes-computer kernel: [10589.448596] input: Microsoft Microsoft IntelliMouse® Explorer as /devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.0/input/input11
Jan 15 11:48:33 kayes-computer kernel: [10589.448706] generic-usb 0003:045E:001E.000B: input,hidraw0: USB HID v1.00 Mouse [Microsoft Microsoft IntelliMouse® Explorer] on usb-0000:00:1d.1-1/input0
Jan 15 11:48:33 kayes-computer mtp-probe: bus: 3, device: 11 was not an MTP device

though I can't confirm if these are directly associated with the "pauses".

Any thoughts on what might be causing this or what else I can do to diagnose the problem?