This is not specific to Ubuntu 13.04; I had this problem before too. That is, after waking up the machine from a suspend, the keyboard doesn’t work properly. Not all key presses are accepted, only about 70% of them. Hitting the keys stronger helps but I don’t want to break the keyboard :)
I’ve found a stupid workaround but it works :) It’s a USB keyboard and pulling out the cable and reconnecting it fixes the issue. If someone has a more elegant solution, please tell me.
Yesterday evening something strange happened to my laptop keyboard. Some keys on the right side stopped working correctly thus it became unusable.
I switched to console with CTRL+ALT+F1 but the problem remained. I rebooted the machine, it didn’t help. I booted to Windows but it was working fine there. Hmm, so the hardware is OK. But why is it not working under Ubuntu? This morning I switched it on hoping that a night rest might have solved the problem :), but no luck. I have a USB keyboard, so I could use the system with that, but what’s wrong with the original keyboard?
Then I found the problem… Num Lock was pressed by accident :))) Holy crap. I use Midnight Commander a lot and Num Lock is right next to Insert, so I must have pressed it by accident. Strangely, Num Lock remains on after switching off and on the computer.
The important thing is that my keyboard is fine and it works correctly again :)