Re: [Linux-fbdev-devel] Reading the EDID block for x86 machines

[Jon S. <jon...@ya...>]

--- Antonino Daplas <ad...@po...> wrote:
> > > 3.  write to PCI config space of secondary
> controller the address you
> > > want it to appear (ie C000:0000).  Can I use
> other addresses?
> 
> I checked the PCI 2.2 specs, and it doesn't have
> this capability.  It
> will give you the address of the expansion ROM, but
> you still have to
> manually copy the ROM and place it in any of the
> expansion areas. 
> Unfortunately for VGA controllers, it's always
> C000:0000.  

You can very definitely move the ROMs to where ever
you want that isn't occupied by something else. I have
written code that does it. Also, the system BIOS must
be moving the ROMs in order to sort things out so that
they don't all appear on top of each other.

You don't even need to move the ROM. Just enable it
and read it's address form PCI space.  The system BIOS
will have sorted the addresses out so that they don't
overlap. PCI config Region 6 is always the ROM see
include/linux/pci.h

> 1.  COOO:0000 will be write protected by the BIOS
> upon initialization of
> the first VGA controller.  This will prevent copying
> of the succeeding
> ROMS into that segment (unless you have a BIOS that
> supports read-write
> shadow ROM's).

How is C000 write protected? I'm pretty sure that the
ATI ROM are writing to C000.

=====
Jon Smirl
jon...@ya...

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