Comment 15 for bug 261084

In general, X is less involved in hotkey management than before. It's not completely out of the picture quite yet, so there's still some chance of X interfering.

However, from what I can tell, when X is involved in handling the sleep key, you should see something like "XF86Standby" listed in the xev output. If X were issuing the key twice, that should show up (at least) twice. I didn't spot it in the xev output though, which leads me to think that the error occurs at a deeper layer.

Fwiw, I've seen acpi-support bug reports about double-hotkey events, in particular brightness keys. So it wouldn't surprise me if this is an acpi-support bug (or at a lower level).

A few experiments that would help narrow things down:

a. In gnome-keyboard-properties, can you map the standby action to some action such as launching the calculator? If X is passing double events, this should launch two copies of the calculator.

b. acpi-support uses scripts in /etc/acpi to handle hotkey events, such as sleepbtn.sh. Experiment with adding lines to have them log to a file, to see if they're getting called. If it happens that the script is getting triggered twice, a quirk could be added to make it ignore the second one.

c. Shut down /etc/init.d/acpid, cat /proc/acpi/event, and hit the key. You should see a single entry there; if two appear, that suggests possibly something at the kernel level. (On my system I see no output, which I think means that X is stealing it.)

Hope this helps, good luck.