Re: [Wg-test-framework] linux 3.14.34 failure to detect disks on C600 storage controller

["Dugger, Donald D" <donald.d.dugger@xxxxxxxxx>]

I still think it's the initfs.  There's a lot of magic that happens when 
creating the initfs and I've been burned by the magic getting confused in the 
past.

I guess I need to understand your build process better.  If you are building a 
kernel on machine A and then booting on machine B you can get hit by subtle 
issues in the build process.  The biggest issue is that, when creating the 
initfs, by default the system identifies which kernel modules to include in the 
initfs based upon what kernel modules are currently loaded on the build 
machine.  If your build machine, for example, is using IDE disks and the target 
machine is running SCSI expect to have problems.

On a related note, I've run into issues where Linux has split a module into 2 
separate modules which confuses the initfs magic and required manual 
intervention.

Another thing to try is to upgrade the Debian kernel on this machine.  You say 
that Debian wheezy running 3.2 works, can you just update the that machine to 
sid (which uses the 3.16) kernel and then see what modules are needed, that 
might tell us what's wrong.

--
Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
Ph: 303/443-3786

-----Original Message-----
From: Ian Jackson [mailto:Ian.Jackson@xxxxxxxxxxxxx] 
Sent: Thursday, April 16, 2015 11:15 AM
To: Dugger, Donald D
Cc: wg-test-framework@xxxxxxxxxxxxxxxxxxxx
Subject: RE: linux 3.14.34 failure to detect disks on C600 storage controller

Dugger, Donald D writes ("RE: linux 3.14.34 failure to detect disks on C600 
storage controller"):
> The other thing I would try is to get a copy of the Debian kernel sources and 
> re-build them the same way you are building the 3.14 kernel.  If a hand built 
> Debian kernel doesn't work then that would be solid proof the problem is the 
> configuration and not the code.

You mean to build Debian's 3.2.0-4 with my config ?  I could try that I guess 
but it wouldn't tell us much because it might be that 3.14.34 needs different 
config options to work properly with this controller.

> I'm guessing the problem is in the initfs, typically the initfs is created 
> using modules from the running system.  Are you rebuilding the 3.14 kernel on 
> the failing machine or do you build it on a different system?

You're thinking the problem is initramfs plumbing ?  I'm sure that's not the 
case - that is all automated.  The build is done on some machine (baremetal, 
and in this case it happens that it was one of these same machines) and 
generates build outputs including all the modules.  Then the target machine is 
completely wiped and reinstalled from scratch, and the kernel and modules from 
the build are unpacked onto it and a suitable initramfs created (using the 
standard Debian tools for such things).

Ian.

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