Re: [Astlinux-users] udev vs. hotplug

[Darrick H. (lists) <dha...@dj...>]

Kristian Kielhofner wrote:
> Hello everyone,
> 
>   Darrick recently brought up a good point...  Hotplugging firmware
> for devices (/lib/firmware).  I've been looking into this myself and I
> have determined that the best route would be to add the full
> linux-hotplug package.  This really isn't that big of a deal, the size
> increase is minimal because it's really just a bunch of shell scripts.
>  It ads a level of complexity that I would otherwise not have, but
> that's why it would be run-time optional.
> 
>   However, looking at hotplug made me think about the entire
> management of devices, firmware, etc.  Hotplug has been succeeded in
> most 2.6-based distributions by udev for complete management of
> devices, device nodes, and firmware.
> 
>   I'd rather not implement udev at this stage.  While it seems to be
> much more reliable than devfs+hotplug, it still doesn't seem as simple
> or reliable as static device nodes.

devfs was a nightmare.  udev is much better, but still needs to be 
tested for our use.  There were bugs early on.  Most of that (if not all 
of that) has been worked out.

>   Then again maybe I'm wrong.  What do you think?  Should we start
> with hotplug as an option and move to udev later?  Or is udev worth a
> shot now?

If you're looking at this to support firmware, we need to go all the way 
with udev.  The "hotplug" binary is NOT required with the new kernels 
(2.6.14 and higher).  That stuff was a hack.  This page explains the 
details farther:

http://vrfy.org/log/recent-state-of-udev.html

The so called "hotplug" package that is currently in trunk should be 
removed.  It's based on something so old that it does nothing but cause 
confusion/harm.

I'd say we move on getting udev implemented in trunk after immediately 
creating a 0.5 branch.  udev would then become part of 0.6.  It's a big 
change so we should allow some time to work out the kinks.

Darrick
-- 
Darrick Hartman
DJH Solutions, LLC
http://www.djhsolutions.com