Patches to enable sound on RISC PC's with 16-bit DACs
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2002/03/03

This patch is to the kernel sources of the acorn32 system to allow
machines fitted with 16-bit DACs to play audio files.  Although it
should work on A7000 series machines, it has not been tested there.

The code has not been installed in the main kernel sources because it
is severely lacking in several respects:

- The DMA code is still a mess, and is still waiting for a
  bus-specific DMA driver to be written.
- The tail of each audio file is being truncated (most noticable on
  very short sounds).
- the beep device is still somewhat of a hack.

To apply the patch:

cd to /usr/src/sys/arch
patch -p0 < .../sound16
cd acorn32/conf
/usr/sbin/config
cd ../compile/GENERIC
make

install kernel and away you go.  The 16-bit sound will only be
activated if you pass the option "sound16" to the bootloader (I
haven't worked out how to detect the 16-bit system at boot time yet).

If you have your own kernel config you will need to delete the old
beep device (at vidc?) and add a new one at audio?  This is logically
the correct place for the beep on this class of machine.

Richard Earnshaw