modprobe.conf: what should be in there.... ?

[Todd Denniston]

Tom London wrote, On 03/14/2008 02:47 PM:
> On Fri, Mar 14, 2008 at 11:20 AM, Bill Nottingham <notting at redhat.com> wrote:
>> Tom London (selinux at gmail.com) said:
>>  > So I'm curious..... what actually needs to be in modprobe.conf?
>>  >
>>  > Here is the one currently installed:
>>  >
>>  > alias scsi_hostadapter ahci
>>  > options snd cards_limit=8
>>  > alias snd-card-0 snd-hda-intel
>>  > alias snd-card-1 snd-usb-audio
>>  > options snd-hda-intel index=0
>>  > options snd-usb-audio index=1
>>  > remove snd-hda-intel { /sbin/salsa -s 0 >/dev/null 2>&1 || : ; };
>>  > /sbin/modprobe -r --ignore-remove snd-hda-intel
>>  > alias eth0 e1000
>>  >
>>  > Are any of these really needed?
>>
>>  No. The remove line for snd-hda-uintel actually does something useful,
>>  but considering you're very unlikely to actually remove the module...
>>
>>  Bill
> 
> Cool.  I renamed /etc/modprobe.conf to /etc/modprobe.conf.last and rebooted.
> 
> Haven't noticed any issues: network is up (as eth0 even!), and
> pulseaudio/sound came up as well.
> 
> One fewer thing to maintain is always good!
> 
> I don't remember who/when the "scsi_hostadapter" line got inserted,
> but I'm presuming the new stuff will "just work" with USB hard drives,
> etc.
> 
> Thanks!
> 
> tom
> 

Careful,
I have had issues in the past where I wanted to test changes to modprobe.conf 
for some scsi settings...
I learned that (at least with some older systems, not sure about current ones) 
the contents of modprobe.conf get [put into||used in the building of] the 
initrd and until you build a new initrd the old settings continue to get used.

suggestion, make a backup of your current initrd and build a new one, then reboot.

Assuming the running kernel is the wan you want to do it for, then something like:
cp -p /boot/initrd-`uname -r`.img \
	/boot/initrd-`uname -r`.img.worked
/sbin/new-kernel-pkg --package kernel \
	--mkinitrd --depmod --install `uname -r`

use with care, and you may want to add a grub entry that uses the same kernel 
and the ".worked" initrd, in case you need to get back where you are now.

-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter