This revision includes some checking to see if your system can run
without udev. In general, if you use any of...
* GNOME
* KDE
* XFCE
* lvm2
... you probably need udev, so mdev is not for you. I've also found one
situation where I need to take one extra step to run without udev. I
have a laptop with a Radeon GPU that requires a binary blob for the
video driver. emerging radeon-ucode downloads a whole slew of binary
blobs, to support umpteen different models. If I leave all the binary
blobs in the library directory, the kernwl needs udev to figure out
which one of the many binary blobs to load. If I remove all the other
binary blobs, and leave only the correct one in the library directory,
it loads automatically.
There is one more imperfect sanity check you can run to check for udev
dependancy if none of the above apply...
a) add the line
sys-fs/udev
to /etc/portage/package.mask
b) execute the 2 commands
emerge -pv system
emerge -pv world
c) if the only errors you get are for not being able to re-install udev
as required by virtual/dev-manager-0, you can proceed to the next stage,
Otherwise, remove the "sys-fs/udev" line from /etc/portage/package.mask
and forget about mdev.
Proceed here only if the above stages don't find any udev
dependancies.
The usual warnings apply...
* this is a beta
* use a spare test machine
* if you don't follow the instructions correctly, the result might be
an unbootable linux
* even if you do follow instructions, the result might be an unbootable
linux
1) Set up your kernel to support and automount a devtmpfs filesystem at
/dev
* If you prefer to edit .config directly, set
CONFIG_DEVTMPFS=y and CONFIG_DEVTMPFS_MOUNT=y
* If you prefer "make menuconfig", the route is as shown below. Note
that the "Autount devtmpfs..." option won't appear until you enable
"Maintain a devtmpf..." option.
make menuconfig
Device Drivers --->
Generic Driver Options --->
[*] Maintain a devtmpfs filesystem to mount at /dev
[*] Automount devtmpfs at /dev, after the kernel mounted the rootfs
Once you've made the changes, rebuild the kernel.
2) Set up for emerging busybox. busybox requires the "mdev" flag in
this situation. The "static" flag is probably also a good idea. In
file /etc/portage/package.use add the line
sys-apps/busybox static mdev
Now, "emerge busybox"
3 a) Create /sbin/linuxrc containing at least
#!/bin/busybox ash
mount -t proc proc /proc
mount -t sysfs sysfs /sys
exec /sbin/init
This should be enough for most users. If you have an unusual setup,
you may need additional stuff in there. Remember to
"chmod 744 /sbin/linuxrc" to make it executable.
3 b) In the bootloader "append" line, include "init=/sbin/linuxrc". If
you're using lilo remember to re-run lilo to implement the changes. If
you're using another bootloader, make the equivalant initialization.
4) Remove udev from the services list, and replace it with mdev. Type
the following 2 commands at the command line
rc-update del udev sysinit
rc-update add mdev sysinit
5) reboot to your new kernel. You're now running without using udev.
6) Remove udev as per the following instructions...
* execute the following command at the commandline
emerge --unmerge sys-fs/udev
* In file /etc/portage/package.mask, append the line
sys-fs/udev
Create the file if it doesn't already exist. You now have a totally
udev-free machine
--
Walter Dnes <waltd...@waltdnes.org>
