Comment 45 for bug 561390

On Thu, Oct 07, 2010 at 07:05:36AM -0000, Kelsey Thornton wrote:
> "Some idiot thought it'd be a good idea if device mapper didn't respond
> to "add" events, like those during boot. Take their change out back and
> shoot it in the head. LP: #561390."

Unless the kernel has been customised, udev add events issued by dm tell
userspace nothing useful and must be ignored. Change events are the ones
to act upon as they indicate that there is a device available for use.
If you're having problems in this area, take a look at how the latest
versions of other distros have packaged the upstream releases and made it all
work together successfully e.g. Fedora/RHEL or SuSE (but not Debian).