Bug#401916:

[David Härdeman <david@hardeman.nu>]

On Tue, Feb 06, 2007 at 11:14:34AM +0100, Michael Prokop wrote:
> * David Härdeman <david@hardeman.nu> [20070201 18:08]:
> >  On Thu, Feb 01, 2007 at 05:16:11PM +0100, maximilian attems wrote:
> > > On Thu, Feb 01, 2007 at 04:38:03PM +0100, David Härdeman wrote:
> > >> So, as a workaround for Etch until this is fixed (presumably by upstream
> > >> changes to udev and/or the kernel), how about changing the following lines
> > >> in the udev initramfs script:
> > >>   udevtrigger
> > >>   udevsettle || true
> > >> to something like this:
> > >>   udevtrigger
> > >>   udevsettle || true
> > >>   while ps | grep -q "[usb-stor-scan]"; do
> > >>       sleep 1;
> > >>   done
> > >>   while ps | grep -q "[scsi_scan_.*]"; do
> > >>       sleep 1;
> > >>   done
> > >>   udevsettle || true
>
> Ok, after running several different tests: nope, this does not fix
> the problem. The usb stuff is running very asynchron. :(
> ...
> I tried to find out what other distributions do and I like the
> approaches of for example OLPC and SuSE. They use an udev rule for
> creating the /dev/root device as an symlink to the main device,
> like:
>
>  SUBSYSTEM=="block", SYSFS{dev}=="$major:$minor", SYMLINK+="root"
>
> I tried to adopt the code for Debian's initramfs-tools but udev does
> not work as I expect it to (I do not find any devices inside /dev
> created by udev - huh?!) so I could not resolve the issue so far. :(

Unfortunately this wouldn't work because scripts which are independent 
of udev might also bring up the root partition (e.g. lvm, evms, 
cryptsetup). At least that is my understanding...

> ...
> Any further tips, hints,... what I could try?

Could you try these lines in the udev script and then mail the contents 
of /begin.ps, /middle.ps and /finish.ps? It would be interesting to see 
if we can find out why the previously suggested approach didn't work:

udevtrigger
udevsettle || true
ps > /begin.ps
while ps | grep -q "usb-stor-scan"; do
 sleep 1;
done
while ps | grep -q "scsi_scan_"; do
 sleep 1;
done
ps > /middle.ps
udevsettle || true
ps > /finish.ps


--
David Härdeman