[Udpcast] Getting info from ACPI - need to make kernel

Alain Knaff alain.knaff at lll.lu
Fri Apr 30 17:47:48 CEST 2004

begin  Friday 30 April 2004 16:41, Donald Teed quote:
> During imaging, I am going to be grabbing information for our
> database such as BIOS service tag from Dell, MAC address, etc.
> I may be asked if I can also supply the battery pack serial number.
> I've noticed that I can get part of the battery info from under
> /proc/acpi/battery/BAT0/info .  The 2.4.26 kernel linked on the
> udpcast website doesn't include ACPI support, so I'm trying to
> compile my own kernel.  I've had limited success.  I've done
> this sort of thing before, just not for a PXE boot environment.

If you need to compile your own kernel, it's actually quite easy: just
download the .config file from
http://udpcast.linux.lu/current/udpc-config26.txt and copy it to
/usr/src/linux/.config (or whereever you compile your kernel)

The udpc-config26.txt is for 2.6 kernels, whereas udpc-config.txt is
for 2.4 kernels.

Then do "make oldconfig" to activate this config file.
Then do "make config" to add any features that may be needed in
addition to those that udpcast needs.

> I need to be able to support the ipappend 1 option in default,

This is an option that is supplied by pxelinux. No need to change
anything in the kernel options for this.
The ipappend system works as follows:

 - pxelinux adds an ip= boot parameter which contains the information
it got grom PXE (which includes IP, netmask, etc.)
 - the udpcast boot loader then reads it from its environment using

The kernel does not really get involved by itself, except to copy it
over from the boot command line to the application's environment (just
like it does with any other boot command line option).

> and this requires the config option "IP: kernel level autoconfiguration"
> and DHCP/BOOTP under it.

This is not needed. What this option would be for is if you had a
kernel without initrd which mounted its root filesystem from NFS. In
that case, the kernel would use the contents of ip= to autoconfigure
itself and automatically mount the root fs. In order to use this, you
would also need to compile all other needed functionality (network
module, NFS filesystem support, etc) into the kernel, rather than as a

In UDPcast's case, we do use an initrd, an everything happens in
application space.

>  I'm not sure what network file
> system options must be provided.

None. The current version of udpcast does not use NFS (although an
older version did).

>  I don't really need
> to mount anything on NCP/NFS, etc, but just a normal
> PXE boot using initrd.  I saw the sample config file for
> floppy based boot, but it was not close enough for what
> one needs in a PXE boot.
> --Donald Teed

The kernel config file is the same for all scenarios: floppy, CD, PXE,
etherboot (although there is a different file for 2.4.x kernels than
for 2.6.x)

[There is a different busybox config file though for floppy and the
other boot methods: .config.mini for floppy and .config.maxi for
everything else]



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