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

[Antonino D. <ad...@po...>]

On Wed, 2003-03-12 at 07:42, Jon Smirl wrote:
> --- Antonino Daplas <ad...@po...> wrote:
> > Yikes!  No, it can't be done this way.  During the
> > early boot sequence,
> > the kernel is not yet decompressed and loaded, so
> > all the services the
> > kernel provides are still unavailable.  Unless you
> > want to walk, detect,
> > enable, etc the PCI subsystem in pure 16-bit
> > assembly...
> 
> You don't Linux to look at the PCI subsys you make
> calls into the system BIOS to find the devices.

That's not the only reason.  The problem is in 16-bit mode, the code can
only access an address range up to only 1MB.  PCI resources are located
above 16MB.  So in order to copy the ROM, it might be necessary to
switch to 32-bit mode, copy the ROM, switch back to 16-bit mode, etc.

Unless I missed some imported BIOS calls or other methods to do this or
something similar in real-mode...

Tony