[Gllug] kernel

[Simon A. Boggis]

On Wed, 2004-01-14 at 21:17, Murray KDE wrote:
> can anyone point me at a good kernel compiling howto?
> 
> the top two google answers (on tldp.org and linux.org)
> appear to be awol, and I'm a tad dubious of the later
> results
> 
> http://en.tldp.org/HOWTO/Kernel-HOWTO/
> 
> ----
> 
> Specifically, I have a Debian Woody 2.4.18-bf2.4
> kernel, which appears to be lacking the bluetooth

You'll find your current kernel configuration in:

  /boot/config-2.4.18-bf2.4

or more generally

  /boot/config-X.Y.Z-blah

for any debian packaged kernel (including ones you build yourself using
kernel-package).

If you:

  apt-get install kernel-source-2.4.18

you'll get /usr/src/kernel-source-2.4.18.tar.bz2, which you can unpack,
and copy the above config to:

  <directory kernel is unpacked in>/.config

If you're copying old config to new kernel source you should do "make
oldconfig" in that dir.

Beware that stock debian kernels use initrd with a cramfs patch so IDE,
SCSI support and ext2/ext3 are modules - if you plan to use a stock
kernel instead of debian's and plan on starting from the config they
use, you'll need to do one of:

  * patch it for cramfs like the debian ones
  * reconfigure it to have the things you need to get booted built in:
    typically enough stuff for ide disks and ext2 or 3 for a desktop 
    system.
  * reconfigure it and figure out how to do initrd with another 
    kind of filesystem than cramfs

I personally like to use make-kpkg to build debian packages of kernels -
as well as building neat packages it takes care of initrd (if used),
which you'll find in package "kernel-package", with instructions in
/usr/share/doc/kernel-package/. BTW if you're building the debian way
you should also install the source for any non-kernel modules packages
and unpack into /usr/src/modules (e.g. alsa).

modules.  Ideally, I'd like exactly what I have now,
> plus the bluetooth bits, and I'm not sure how to
> figure out what the current configuration is - given
> it can down via apt-get.

Before you waste time rebuilding the 2.4.18 kernel, make sure that the
bluetooth stuff you want is properly supported in that kernel. My hazy
memory of this is that there are serious bugs in the USB code earlier
than 2.4.20 or so (for which debian may or may not have patched, I don't
know) which prevented USB bluetooth dongles working very well in some
modes of operation (since a lot of bluetooth stuff seems to go as
serial-over-usb).

The 2.4.18-bf2.4 kernel is probably a little old now, I'd personally go
newer if I were taking the trouble to rebuild anyway. I've had good
experiences getting the bluez bluetooth stuff to work under debian, but
my most heavy use has been recent under sarge and sid with > 2.4.21
kernels.

Simon

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