Hello.

As some of you know, I am maintaining a
driver for pc-speaker, which can be
downloaded here:
http://www.geocities.com/stssppnn/pcsp.html

I've been asked several times to if not
get the driver included into the mainstream
kernel, then at least make it fully modular.
For this I need a couple of small hooks
to be included into the kernel.
The patch that adds all the necessary
hooks is attached. It doesn't (intended to)
change any existing functionality so it
must be absolutely harmless.
It is against 2.4.20 but it can be applied
to anything up to 2.4.21-rc1-ac1 with some
offsets.

Detailed explanation of the patch follows:
- use_speaker_beep variable controls
whether the kd_mksound() can produce a
beeps. By default is set to 1.
- Added SA_FIRST flag to add the irq handlers
to the head of the chain. Kernel's timer
irq handler produces a big latency so
that if the pcsp handler is executed
after it, the sound is horribly distorted.
- pit_counter0_offset is the variable
that gets added to the value got from
PIT counter. pscp driver alters the
counter so the correction is necessary.
Introduced read_pit_counter0() for that
purpose.
- handle_timer_irq variable controls
whether the kernel's timer handler is
to be executed or not. 1 by default.
- use SA_SHIRQ flag for the kernel's timer
irq handler to allow the driver to handle
that irq as well.

I think this patch is trivial and probably
can be applied to some testing tree in
order to get the pc-speaker driver a chance
for surviving :-)
Let me know if you feel the patch needs
more work.