Arch Linux

arctor

Member

Registered: 2011-10-22

Posts: 21

Removing Udev?

Can someone explain to me the procedure for replacing udev with specific modules in mkinitcpio.conf ?

I don't see any place that describes how to discover the modules I would need to add under MODULES=() in mkinitcpio.conf other than a blurb mentioning hwdetect but nothing specific.

From the wiki

https://wiki.archlinux.org/index.php/Mkinitcpio#MODULES

The MODULES array is used to specify modules to load before anything else is done. To accelerate the boot process, users may opt to disable the udev hook and list required modules here instead:

MODULES="piix ide_disk reiserfs"

[...]

HOOKS="base autodetect ide filesystems"

falconindy

Developer

From: New York, USA

Registered: 2009-10-22

Posts: 4,111

Website

Re: Removing Udev?

Generally, when you have a reason to do this, you also have the understanding of your own hardware and of early boot to do this on your own. So, really, I have to ask. Why? Additionally, I'll point out that the wiki is wrong. Having any subsystem hooks in your config after removing udev is worthless. You need to specify every top level module (i.e. no need to list dependencies) in the MODULES array anyways.

Easy method:

boot with udev, drop into a ramfs prompt, and type lsmod. Assuming that when you leave that prompt you'll boot successfully, that's what you need to boot.

Last edited by falconindy (2011-11-02 00:29:24)

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arctor

Member

Registered: 2011-10-22

Posts: 21

Re: Removing Udev?

Generally, when you have a reason to do this, you also have the understanding of your own hardware and of early boot to do this on your own. So, really, I have to ask. Why? Additionally, I'll point out that the wiki is wrong. Having any subsystem hooks in your config after removing udev is worthless. You need to specify every top level module (i.e. no need to list dependencies) in the MODULES array anyways.

Easy method:

boot with udev, drop into a ramfs prompt, and type lsmod. Assuming that when you leave that prompt you'll boot successfully, that's what you need to boot.

I am doing it to improve/streamline the boot process and gain a better understanding on how it works....

I wish you would have told me that I needed to add "break=y" to the kernel options at boot in order to get a ramfs prompt... spent a while trying to find a way to "drop into" one.

This is what I ended up with...

MODULES="i915 ext4 ahci sd_mod"

[...]

HOOKS="base autodetect encrypt lvm2"

Now I am trying to figure out a few more things..

1. Is there any reason to keep autodetect in hooks?
2. How to fix fgetty when it errors out with "could not chown/chmod tty device"..

falconindy

Developer

From: New York, USA

Registered: 2009-10-22

Posts: 4,111

Website

Re: Removing Udev?

Now I am trying to figure out a few more things..

1. Is there any reason to keep autodetect in hooks?

Probably not. You can use lsinitcpio (included with mkinitcpio) to dump the contents of an autodetect and non-autodetect image and see what, if any, the difference is. I suspect there won't be a difference.

2. How to fix fgetty when it errors out with "could not chown/chmod tty device"..

No idea. I'll go out on a limb and blame fgetty. Does agetty exhibit the same issue?

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arctor

Member

Registered: 2011-10-22

Posts: 21

Re: Removing Udev?

Probably not. You can use lsinitcpio (included with mkinitcpio) to dump the contents of an autodetect and non-autodetect image and see what, if any, the difference is. I suspect there won't be a difference.

Tried that and see no change... autodetect is not even listed under the hooks section of the output. Thanks for the info

No idea. I'll go out on a limb and blame fgetty. Does agetty exhibit the same issue?

agetty is perfectly fine... tried fgetty in order to lighten the load a bit more on the netbook (Aspire One D250) this is for and it gives that error on boot and keeps respawning to fast never getting a prompt :\

Last edited by arctor (2011-11-03 14:56:44)

riemannia

Member

From: Salt Lake City, UT

Registered: 2012-05-20

Posts: 4

Re: Removing Udev?

bump, I'm having the same "fgetty could not chown/chmod tty device" problem

riemannia

Member

From: Salt Lake City, UT

Registered: 2012-05-20

Posts: 4

Re: Removing Udev?

arctor, I figured out why I was getting the "could not chown/chmod tty device" error.  Before I started using fgetty, I had

c1:2345:respawn:/sbin/agetty -8 -s 38400 tty1 linux
c2:2345:respawn:/sbin/agetty -8 -s 38400 tty2 linux

in my /etc/inittab.  To start using fgetty, I changed it to the following:

c1:2345:respawn:/sbin/fgetty -8 -s 38400 tty1 linux
c2:2345:respawn:/sbin/fgetty -8 -s 38400 tty2 linux

Replacing this with

c1:2345:respawn:/sbin/fgetty tty1 linux
c2:2345:respawn:/sbin/fgetty tty2 linux

solves the problem.