Comment 4 for bug 1054292

I'm not 100% positive I'm seeing the exact same issue, but I think I am. In my case, the xorg-edgers PPA is not installed, though. I've got a 12.04.3 installation on a Lenovo Ideapad laptop with an encrypted root filesystem. When I boot with a stock kernel, I'm able to type my encrypted filesystem passphrase only on the laptop's built-in keyboard, not on any USB keyboard I might have attached. The USB keyboard works fine in my boot manager and once the system is fully booted (for the X login screen, for instance); it's only when typing in the encrypted-filesystem passphrase that the problem occurs.

I worked around the problem by compiling my own kernel and changing several USB-related options changed from "m" to "y". I *THINK* that the relevant one was CONFIG_HID_GENERIC or CONFIG_USB_HID, but I made several simultaneous changes, so I can't be sure of that.