Comment 6 for bug 691826

Drop to the console with Ctrl-Alt-F1 and login with your username and password (Warning: Return to the graphical screen again with Ctrl-Alt-F7!)

Run:

sudo showkey -k | tee -a hotkey-log.txt

ignore the first 0x9c that may show up---this is the result of you letting go of the return key!

Pressing and letting go of the non-working hotkey should now produce output similar:

0xe0 0x1f 0xe0 0x9f

the first half are the key-press and second-half are the key-release, please report this line (a log of what you did has been saved in hotkey-log.txt to help you).

Wait 10 seconds for showkey to exit.

Attach here the generated file that you can find in your home.
I'm italian, but here we can talk only English.
Thanks
Fabio