2.4 Kernel hacking question

Hello everybody,

as already mentioned in some earlier post, I've backported
the most
recent BlueZ modules from kernel 2.4.31-mh1 to a custom
kernel 2.4.20.

I know that the 2.4 branch is considered unsupported by now,
but maybe
somebody can answer my question regardless:

in rfcomm/tty.c, line 592, a function tty_wakeup() is used
that isn't
available in 2.4.20 yet. Can anybody tell me what exactly
this function
is supposed to do so that I can look for a workaround? (*)

CU Florian

(*) I've already looked at the kernel source, of course.
Still haven't
got a real clue, though.. :-/