dracut: ide vs ata modules

Kacper Kornet draenog at pld-linux.org
Tue Apr 1 10:23:15 CEST 2014

On Fri, Mar 28, 2014 at 09:22:41PM +0100, Marcin Krol wrote:
> >I think the second option is the simplest one, so I would like to
> >implement it in  PLD, unless someone has preference.

> Personally I'm using dracut with host-only option enabled. It uses
> system wide module blacklist and includes only modules for supported
> hardware in initramfs, not all of them. I've not encountered (yet)
> machine on which host-only config would prefer IDE drivers over SATA
> ones but perhaps it depends on hardware used.

Try qemu. Even image generated by dracut -H contains both piix and
ata_piix. And unless someone has piix blacklisted in /etc/modprobe.d,
udev loads piix as the first one, and ata_piix only after it.

> If host-only config is not enough then best solution IMO is to patch
> dracut to prefer SATA drivers over IDE. It can be done by checking
> device class if more than one module is available.

I think dracut does something like:

udevadm trigger --type=subsystems --action=add
udevadm trigger --type=devices --action=add

and the module are loaded by rule:

DRIVER!="?*", ENV{MODALIAS}=="?*", RUN{builtin}="kmod load $env{MODALIAS}"

so the order is dictated by modprobe <alias>. Hence my idea is to change 
this order. Patching dracut/udev would be probably more complicated.


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