Hi! Looks like all callback-specific hrtimer support has been removed from the 2.6.xx stable tree. http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6-stable.git;a=history;f=include/linux/hrtimer.h;h=bd37078c2d7d7ceb9f9f7b9bd2340724ae29c73d;hb=HEAD Regards, Patrik