Comment 7 for bug 23374

(In reply to comment #6)
> Hm, well, you're right (manually adding CONFIG_MAGIC_SYSRQ=y to the config file
> and rebuilding didn't affect anything, but there's no mention of it in the
> /boot/config-* file, which confused me), but unfortunately, I'm not able to get
> the Magic SysRq key to work. Alt-sysrq-1 and altl-sysrq-t unfortunately behave
> just like alt-1 and alt-t. (I've also tried the other permutations of ctrl and
> alt, with no success)
>
> For what it's worth, I also tried the magic sysrq key in a working kernel, and
> with a different keyboard, to no effect.

Perhaps you aren't using an Ubuntu kernel.

mizar:[~] grep SYSRQ /boot/config*
/boot/config-2.6.12-3-k7:CONFIG_MAGIC_SYSRQ=y
/boot/config-2.6.12-7-k7:CONFIG_MAGIC_SYSRQ=y
/boot/config-2.6.12-8-k7:CONFIG_MAGIC_SYSRQ=y
/boot/config-2.6.12-9-k7:CONFIG_MAGIC_SYSRQ=y