Arch Linux

Altay_H

Member

Registered: 2009-01-31

Posts: 40

Necessary MODULES in rc.conf [SOLVED]

I noticed that I have a rather large number of modules set to load up in my rc.conf file:

MODULES=(8139cp 8139too mii b43 !b43legacy !bcm43xx ac97_bus snd-mixer-oss snd-pcm-oss snd-page-alloc snd-pcm snd-timer snd snd-ac97-codec snd-atiixp-modem snd-atiixp soundcore)

I know that b43 is necessary for my wireless card to work, and I suspect some of the other modules are necessary for sound and suspend to work, but it seems like I might have some unnecessary modules. Is there an easy way to know which modules I need?

I also noticed that the rc.conf.pacnew file pacman created has an empty list for modules. Is this because no modules are strictly necessary, or because which modules are necessary differs vastly?

Last edited by Altay_H (2010-02-07 19:26:31)

Misfit138

Misfit Emeritus

From: USA

Registered: 2006-11-27

Posts: 4,189

Re: Necessary MODULES in rc.conf [SOLVED]

udev is quite reliable (though not perfect) at taking a hardware inventory and loading all necessary modules nowadays.
You may want to remove all modules from that array, reboot and see if everything is operable.
That array is still very useful and versatile, though; it allows you to specify modules that udev may miss, as well as the order in which they load if this is preferable or necessary.

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Sauengard

Altay_H

Member

Registered: 2009-01-31

Posts: 40

Re: Necessary MODULES in rc.conf [SOLVED]

I left the MODULES array empty and rebooted and everything seems to be working correctly. It seems like it's booting a bit faster too. Thanks for the help.

sj87

Member

Registered: 2010-02-06

Posts: 6

Re: Necessary MODULES in rc.conf [SOLVED]

It should be booting a little bit slower actually. 1-3 seconds slower so nothing critical.

Besides, the MODULES array can be configured and still udev could be used. If you want to disable udev, you need to set MOD_AUTOLOAD="false" in rc.conf. Sometimes it is necessary to add modules manually - like the VirtualBox driver vboxdrv, which isn't used for any real device so it's not detected by udev. You can add only that module and udev figures out the rest on boot.

Last edited by sj87 (2010-02-08 18:02:22)

Altay_H

Member

Registered: 2009-01-31

Posts: 40

Re: Necessary MODULES in rc.conf [SOLVED]

I was curious whether or not it's actually booting any faster, so I timed the boot from grub to login prompt. It loaded in almost exactly 17 seconds every time regardless of whether or not the MODULES array was empty. I guess it goes to show that perceptions can be inaccurate.

I disabled udev to see how much time it would save, and it was between 0.5 and 1.0 seconds faster. Unfortunately it broke suspend, and one second is a small price to pay for udev, so I'll just be using udev for now.