Re: SNB PCI root information

[Ingo Molnar <mingo@kernel.org>]

* Yinghai Lu <yinghai@kernel.org> wrote:

> On Wed, Jun 20, 2012 at 11:46 AM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> 
> > As far as I can tell, here's Yinghai's recommendation:  the 
> > user argument should not override BIOS _PXM because if the 
> > BIOS gets the _PXM wrong, the user won't be able to work 
> > around it with the argument, which will force the vendor to 
> > fix the BIOS.
> >
> > I'm not buying it.  The convention that user-supplied 
> > arguments always take precedence is useful, easy to 
> > document, and matches user expectations.  It allows the user 
> > to work around both missing _PXM and incorrect _PXM.
> 
> if the vendor provide _PXM, that _PXM should be right and be 
> trusted.
> 
> if the vendor does not provide _PXM, we can have command line 
> to input it before user can get one updated BIOS from vendor.

So how about an incorrect _PXM, or a slightly inefficient one? 
Why shouldn't it be possible for the user to override it?

I mean, if we create a parameter space that tweaks data then why 
not make it complete and allow *all* firmware data to be 
(optionally) modified, from the kernel boot line?

Thanks,

	Ingo