Public SourceMage Discussion List

[The Well-Beloved Bard <dezmond AT bardicgrove.org>]

Careful, Andrew - no need to flame someone who's trying to share knowledge 
here.  I know devfsd makes the links for you.  However, I have run into a 
problem with devfsd that I thought other people might want to be aware of 
so that it wouldn't bite them like it did me.

Devfsd _only_ creates links for the devices it knows about.  So, if it 
doesn't know about the device, it can't make a link.  If the SCSI driver 
is compiled into the kernel, it's not loaded when devfsd creates its 
links.  Since it's not loaded, /dev/sdAX aren't populated, so devfsd 
doesn't do anything with it.  Because devfs is mounting on /dev, it 
"hides" the /dev/sdAX entries, so when you get to the kernel (that has the 
driver statically compiled in), the driver tries to assign /dev/sdAX 
values to the drives connected to the SCSI adapter, but can't, because 
those special block devices are "hidden" by the mount, and aren't visible 
to the driver.

This is not a big deal, as long as you don't compile the SCSI controller 
driver statically.  If you do have the SCSI controller drivers compiled 
in statically, and mount devfs at /dev, however, you don't get to 
access your drives because IT CAN'T MAKE THE LINKS!  I thought that 
since it makes your drives inaccessible until you recompile the driver as 
a module, that I would save people having to bang their heads against a 
wall I'd already found the door to.

--steve--
who remembers when informative messages to the SM lists were welcomed 
instead of flamed...

On Thu, 10 Jul 2003, Andrew wrote:
> devfsd makes the links for you. Im not sure whats so hard to grasp here...
> and if for whatever reason you are scared of devfsd you can making fscking
> symlinks to the 'old' devices you want to use. This isnt rocket science.
> 
> On Thu, Jul 10, 2003 at 07:23:47PM -0700, The Well-Beloved Bard wrote:
> > Just wanted to give a warning to people about something that has bitten 
> > me 
> > in my use of devfs.  The issue I've run into is that if you do not 
> > compile 
> > your SCSI drivers as modules (because you want the slight performance 
> > boost gained by statically compiling them in...) and build them into the 
> > initrd file, devfs won't see the drives attached to the affected 
> > controllers, and won't be able to make its links.  But once devfs comes 
> > up in /dev, the "old" /dev/sdAX entries disappear, so it becomes 
> > difficult 
> > to access the drives.
> > 
> > Has anyone else seen this, and if so, do you know of a solution?
> > 
> > Thanks,
> > --steve--
> > 
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-- 
   I remain, as always,
 In service to His dream.
 --The Well-Beloved Bard--
--dezmond AT bardicgrove.org--