Re: debian and UDEV

[Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>]

Hendrik Sattler <debian@hendrik-sattler.de> writes:

> Am Donnerstag, 18. Mai 2006 19:22 schrieb Goswin von Brederlow:
>> Because the only _solution_ with current userspace is to kill the
>> kernels hotplug design and go back to synchronous handling.
>
> Another solution might be to dynamically attach to udev events. This is how 
> in-kernel async device discovery is handled and correctly done, this is 
> without race conditions:
> * register a function/program for new devices of your choice
> * load the proper module
> * your previously registers function will be run

But how do you detect when there is no device to be found to call the
function?

Say you have a scsi controler with no harddisks attached. You boot,
you register a "continue booting" function for the scsi disks, load
the scsi modules and then you hang. Bugger.

So you have to add a timeout again which means a race condition or
too long delay.

You end up with polling and displaying "waiting for /" in a loop.


People are saying this is a good thing because then you can hotplug
your scsi disk or usb stick that has your / on it and it will continue
booting.

MfG
        Goswin