>> Agreed. I've never looked at this code, but it seems to ask for a 
>> root path right before trying to load init but apparently there's a 
>> little more happening in between - shouldn't be /that/ hard to figure 
>> out.
>
> I would think that ideally, you'd want the USB baseline drivers 
> started very
> early, and the USB mass storage detection to happen "much later".  I 
> bet
> the USB drivers don't "factor" nicely like that. ;->

It'd be easy to do if you leave the umass driver out of the kernel and 
then load it as an LKM later on. To really solve media device ordering 
we would need a hotplug like API that keeps track of devices by serial 
number and assigns a controller independent disk name that doesn't 
change.

example:

scsibus0 -> sd3 -> hpd1
detach sd3
hdp1 detached
attach to scsibus1 at a different ID
scsictl scsibus1 scan all all
sd3 at scsibus1
hdp1 at sd3
scsibus0 -> sd1 -> hdp1

That way you can be sure to get the same device regardless of 
controller or device ID ordering. I believe linux hotplug does 
something like this, and they also have the ability to mount file 
systems based on a label assigned by newfs at fs creation time. So you 
would only need label=root instead of a /dev/hdp1 entry. I think we'd 
need to look into devfs at that point as well.