[gobolinux-users] InitRamFS and cpio format

[Aitor Pérez Iturri]

El Thu, 17 May 2007 22:39:07 -0300
"Lucas C. Villa Real" <lucasvr at gobolinux.org> escribió

Hi,

> 
> Just ensure that the necessary drivers for your scsi controller are
> loaded. I've been taking more care of that in the latest kernel
> packages, but it's interesting to check if they're still available as
> modules only.

No problem, i'm using the kernel used to boot my machine.
> 
> I haven't worked with initramfs yet.. at which stage of the boot does
> it run? Do you have a boot log available, just to check if your disk
> was found? Is it possible to mount procfs or sysfs? If that's
> possible, you could check /proc/partitions and /sys/block/ to see if
> your device was detected by the kernel. If it's not, then you'll
> probably need to forget about udev and just create a minimal/static
> /dev in your initramfs with the necessary device nodes.

initramfs does something very close to initrd, the kernel will mount
the cpio file as root and the it will execute the init script. All the
work is done there.
I'm testing it with qemu, and my lvm disk is a sata disk which is
detected and configured as sda (i think lvm looks for sda to create the
volumes). The problem is that i don't know how to tell qemu that i have
a scsi dist, i can pass the -hdb option and now seems to be detected
but remapped to hdb.

> 
> Anyway, udev doesn't use hotplug anymore. All you need to do is to
> call 'udevtrigger' and then 'udevsettle', which checks for the kernel
> events and waits until all events are handled, respectively. The
> following calls are enough to create a functional udev task:

More problems here, the newest udev sources can't compile against klibc
so i'm using 075 version, which has not udevtrigger.
Now seems to work partiallity, i have some devices created, i'm reading
how to write udev rules to rewrite all from scratch for initramfs, in
the stadard rules a lot of programs are called to get info from sys,
and that programs are not compiled when klibc is used, i hope that we
can boot withouth them.

> 
> Prior to the call to udevd you have to have some basic devices in
> /dev, as well as sysfs mounted (procfs is probably needed as well).

Why? In the udev rules there are mappings to build basic devices.

Greets.

Aitor.