Getting started with mdev

Rob Landley rob at landley.net
Thu Dec 14 23:09:41 UTC 2006


On Thursday 14 December 2006 5:39 pm, Trevor Harmon wrote:
> On Dec 14, 2006, at 2:04 PM, Rob Landley wrote:
> 
> > My fault.  What do you need?
> 
> A simple docs/mdev.txt file summarizing the key points mentioned in  
> this thread would have helped a lot.
> 
> > You need /dev/console in your initramfs.  This is a funky kernel  
> > thing.  I
> > don't know why they don't just create it, ask linux-kernel.  The  
> > default
> > initramfs has one.
> 
> What is the "default" initramfs?

If you don't supply an initramfs, you get one with three 
entries: /dev, /dev/console, and /root.

Why that?  Because that was the example output from 
scripts/gen_initramfs_list.sh when you ran it with no arguments, which the 
kernel was doing for a dozen or so versions when you hadn't specified an 
initramfs location in the kernel's .config.  By the time anybody noticed, the 
kernel had developed a dependency on the /dev/console entry in there. :)

These days, gen_initramfs_list.sh produces this default .config file when you 
give it the -d option, and outputs nothing when you run it with no arguments.  
This is considered an improvement.

As far as I know, nothing depends on the /root entry.  It was just part of the 
example config file.  (You need the /dev entry to have a directory to 
put /dev/console in.)

Rob
-- 
"Perfection is reached, not when there is no longer anything to add, but
when there is no longer anything to take away." - Antoine de Saint-Exupery



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