I'm using Ubuntu 14.04 and a Logitech K520 wireless keyboard-mouse set. Occasionally, when I wake up Ubuntu from suspending, I find that the mouse works but the keyboard doesn't. And I find a way to work around this: first use mouse to login with guest account, then the keyboard wakes up also, and then logout the guest account and get keyboard still working.
So this seems to be a bug. Any available patch to fix it?