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Subject: Re: Why do we probe option roms at 2K boundaries?
From: Dan Williams <dan.j.williams@intel.com>
To: Jon Smirl <jonsmirl@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Alan Cox <alan@linux.intel.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Hans de Goede <hdegoede@redhat.com>
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Date: Wed, 15 Jul 2009 17:08:53 -0700
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On Wed, 2009-07-15 at 16:13 -0700, Jon Smirl wrote:
> On Wed, Jul 15, 2009 at 7:10 PM, Alan Cox<alan@lxorguk.ukuu.org.uk> wrote:
> >> interrogating a data structure stored in option-rom memory.  My initial
> >> implementation involved blindly scanning from c0000 to f0000 in 512 byte
> >> increments.  Neil and others pointed out that this may not be a safe
> >
> > It isn't safe. If you hit certain ISA devices your system will drop dead.
> > OTOH I doubt anyone has an intel matrix raid controller and a WD80x3 on
> > the same box ;)
> 
> Random link from google, slide 21
> http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWAR05005_WinHEC05.ppt
> 
> PCI 3.0+ allows 512b alignment, but you must first make sure you are
> on a PCI 3.0+ system.

Thanks, I believe this may be the missing difference between my test
system and Hans'.