Re: [PATCH] aic94xx: Use request_firmware() to provide SAS address if the adapter lacks one

["Darrick J. Wong" <djwong@us.ibm.com>]

On Tue, Oct 09, 2007 at 09:41:47AM -0700, Andrew Vasquez wrote:
> On Tue, 09 Oct 2007, James Smart wrote:
> 
> >  Why do you prefer request_firmware() vs something over sysfs ?
> > 
> >  Does environments like the kdump kernel also have access to data needed
> >  by request_firmware() ?

Assuming the driver-loading parts of the kdump kernel's initrd are the
same (udev, bunch of modules, firmwares, etc) as the regular kernel's
initrd, this shouldn't be a problem.

In the specific case of aic94xx, one needs request_firmware() and
associated infrastructure to load firmware blobs into the controller in
order to issue any I/O at all.

> There's already much in the way of automation and infrastructure
> present in supporting the request_firwmare() interfaces (perhaps not
> the best of names) which can provide for a level of flexibility beyond
> a basic 'soft_port_name' interface.
> 
> Though I don't see why both can't coexist cleanly -- I take it the use
> case you are considering is: software recognizes no valid WWPN
> available, query via request_firmware() fails, software halts
> initialization (rather than fail), and awaits the admin to poke
> '0x123456.. > /sys/.../fc_host/soft_port_name', causing a ping to the
> driver and continuation of initialization with requested portname?

Hmm... could we use such a sysfs attribute to reassign adapter WWNs at
arbitrary times?  Is that even a good idea?

--D