Thread: blacklisting a module

i'm trying figure out how blacklist module (persistently), , following bit confusing:

let's take module "floppy" example. i've gathered, proper procedure is:

1. create .conf file under /etc/modprobe.d/

code:

$ sudo vim /etc/modprobe.d/blacklist-floppy.conf    
blacklist floppy

2. update initrd image:

code:

$ sudo update-initramfs -u

3. reboot

procedure works great, step 2 do? think recreate initrd image slight change, telling not load floppy module, guess implies initrd image responsible telling kernel modules load - assumption correct?

without step 2, change not take effect, , floppy module still running after reboot though blacklist-floppy.conf file present. it, if want unblacklist floppy module, remove file blacklist-floppy.conf , reboot , takes effect - running step 2 again not seem necessary reverse procedure. step 2 doing?

tgalati4@mint14-extensa ~ $ locate floppy.ko
/lib/modules/3.5.0-17-generic/kernel/drivers/block/floppy.ko
/lib/modules/3.5.0-23-generic/kernel/drivers/block/floppy.ko
/lib/modules/3.5.0-25-generic/kernel/drivers/block/floppy.ko
/lib/modules/3.5.0-26-generic/kernel/drivers/block/floppy.ko

if need floppy part of boot process (many years ago did!), loaded initial ram disk file system (initramfs). blacklisting it, not loaded bootstrap process, if have floppy controller on motherboard, kernel may load anyway.

don't have floppy on laptop, in 12.10 don't see floppy module loaded:

tgalati4@mint14-extensa ~ $ lsmod | grep floppy

on desktop floppy header connection, might. can turn floppy off in bios , floppy module not loaded. prove it, take lsmod snapshot of normal boot , print out. go bios , turn off parallel port, serial port, floppy, , don't need. boot again , run lsmod , compare 2 lists. save little ram , maybe few interrupts. important real-time applications, audio/video editing, etc.

think listing module in 1 of many blacklist configuration files enough keep being loaded kernel. if need blacklist module bootstrap/initial kernel run update-initramfs command. , needed if can't boot linux live cd/dvd. it's work-around unsupported or difficult hardware.

also, i'm not sure if need create blacklist-floppy.conf file, because i'm not sure if each file gets read in /etc/modprobe.d. put blacklist floppy in 1 of other conf files.

understand module loading , blacklisting framework (and hardware detection in general) has undergone many changes on years. information may out of date , wrong.

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