mdev.conf

[Natanael Copa]

On Thu, 2009-11-12 at 02:58 +0100, Denys Vlasenko wrote:
...
> Now, what *I* would like, is this example
> to become more useful for its target audience:
> the people why have trouble figuring out how to use mdev,
> or what are the common pitfalls or non-obvious things
> one usually has in mdev.conf.
> 
> Currently, the example does not do it well. For one:
> 
> # block devices
> ram([0-9]*)     root:disk 660 >rd/%1
> loop([0-9]+)    root:disk 660 >loop/%1
> 
> Why rd/*? why loop/*? Is it required for all Linux systems
> (say, some tolls expect these dirs),
> or just a common practice in many distors? Which ones?
> The comment about this is needed.

I dont remember. It was something I found that gentoo udev did and
copied it. Might be that it was something udev used to do but no longer
does.

Looks like those are not needed.


> sd[a-z].*       root:disk 660 */lib/mdev/usbdisk_link
> hd[a-z][0-9]*   root:disk 660 */lib/mdev/ide_links
> 
> What these scripts should do? Why?

Those are Alpine specific.
http://git.alpinelinux.org/cgit/aports/tree/main/busybox-initscripts/usbdisk_link

The idea here was to create a symlink to first found usb disk. Alpine
looks for and store user config from this. It makes it possible to
use /dev/usbdisk in fstab.

I think the ide_links does something similar. At some time there was usb
disks via IDE subsystem IIRC. kernel driver ub i think.

I need to go over those again and delete what obsolete.

> md[0-9]*        root:disk 660
> sr[0-9]*        root:cdrom 660 @ln -sf $MDEV cdrom
> 
> Why not >cdrom ?

I had an issue where an initramfs initscript created the link early. IF
link already exist mdev will not create it. If link was bad, the system
refused to boot.

> and so on.
> 
> I will ask people to refrain from just throwing any random
> cool stuff into the example file. If you want to add something,
> add comments too.
> 
> --
> vda
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