After upgrading to 12.04, my Logitech M515 does not work here is some output from the terminal:

lsusb

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 003: ID 0411:002a BUFFALO INC. (formerly MelCo., Inc.) 
Bus 001 Device 004: ID 055d:3021 Samsung Electro-Mechanics Co. 
Bus 002 Device 002: ID 413c:2005 Dell Computer Corp. RT7D50 Keyboard
Bus 004 Device 002: ID 0582:0074 Roland Corp. EDIROL UA-25
Bus 005 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver

dmesg | grep Logitech

[   30.470528] logitech-djreceiver 0003:046D:C52B.0004: hiddev0,hidraw1: USB HID v1.11 Device [Logitech USB Receiver] on usb-0000:00:1d.3-2/input2

The cursor does not move. Also the mouse was working in 11.10 and is working in Windows NT 5.1.2600.