Comment 29 for bug 54191

Hm, damn.

USB mice are a lot smarter but I am not sure if the kernel takes advantage of that. It looks like this code was just setting every mouse to have 3 buttons:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=drivers/hid/usbhid/usbmouse.c#l180

 180 input_dev->keybit[BIT_WORD(BTN_MOUSE)] = BIT_MASK(BTN_LEFT) |
 181 BIT_MASK(BTN_RIGHT) | BIT_MASK(BTN_MIDDLE);

Anyway, I think 2-button USB mice are so rare that they can be ignored. 2-button touchpads in laptops are common, but they are all PS2 as far as I have seen.

Could we default Emulate3Buttons to off for USB mice, then?