Important Note
These patches are far from stable, so they may be unreliable and may not work on your machine at all (especially on iBooks or newer G4s).
Getting the Patches
You can get the patch from .
Once you have downloaded the patch (for whatever version you have the kernel source for), you can go right ahead and patch the kernel:
Open an xterm. Become root using su -.
Go to the directory where you downloaded the patch to.
Apply the patch by running this command:
bzip2 -d snd-ed19.diff.bz2 | patch -p1
If you downloaded with Netscape, it might have uncompressed it automatically when it saved the file. Most likely if you get an error about not being in bzip2 format, it's uncompressed. You can also prove this using the file snd-ed19.diff.bz2 command, which will tell you if it's compressed or uncompressed.
If it is uncompressed, you can try:
cat snd-ed19.diff.bz2 | patch -p1
Selecting Options & Compiling the Kernel
When you do make menuconfig, go to sound, and check the options you want.
You will probably want to enable DMA Sound In in most cases, unless you have an iBook or don't want to sound input (but then, why would you be compiling this backport ;).
From here, build the kernel the standard way:
make dep
make modules
make modules_install
make vmlinux
Reboot with the new kernel.
Testing 1, 2, 3, Testing... !
When you reboot, you will see info about the new dmasound driver (it's information looks different then the old version), along with info on your sound input chip.
Once it boots, login as root.
Run aumix. If you dislike (or don't understand howto use) it's interactive mode use this command:
aumix -m 100
This should enable your microphone input.
Now you can try recording. It you have your microphone hookup (or another device like a Tape deck hooked up) try:
cat testing.wav < /dev/dsp
This will hopefully create a WAVE file of whatever is coming into the computer. You can stop recording by hitting control-d which is the accelerator for end.
Play it back:
cat testing.wav > /dev/dsp
If it worked, you should get whatever you recorded played back.
Of course there is far more specficated tools for recording sound in Linux, they include aumix (believe it or not ;), KDE Media Player, and several others.
