As of June 18th, under Ubuntu 10.04, fully upgraded, the Logitech G15 keyboard’s extra keys simply do not work.

(II) XINPUT: Adding extended input device "G15 Extra Keys" (type: KEYBOARD)
(**) Option "xkb_rules" "evdev"
(**) Option "xkb_model" "logitech_g15"
(**) Option "xkb_layout" "us"
(II) XKB: generating xkmfile /var/lib/xkb/server-D378AD8F86E560F712A83EE36E4E5E92C595B9BD.xkm
G15 Extra Keys: dropping event due to full queue!
G15 Extra Keys: dropping event due to full queue!
G15 Extra Keys: dropping event due to full queue!

No output is shown in xev, and the inability to use my keyboard’s full range of powers makes me a sad panda. Sadly, this state of affairs has apparently been in effect since early April, as evidenced by the bug report on Ubuntu’s issue tracker. Oddly, that very same tracker has a user-submitted patch (dating from late April) which has been verified to fix the issue, someone reporting success with it, and…the very first developer response was two weeks ago.

But Ubuntu development timeliness is hardly my bailiwick. Here’s how to get the fixit patch if you happen to be an Ubuntu user with a G15, instructions shamelessly stolen from Niels Slot:

apt-get source g15daemon
cd g15daemon-1.9.5.3/
wget http://launchpadlibrarian.net/46395768/make-g-keys-work-again.patch
patch -p1 < make-g-keys-work-again.patch
dpkg-buildpackage
cd ..
dpkg -i *.deb

So there you have it, now your G15 works too.