Re: [patch 2.5] VGA IO on systems with multiple PCI IO domains

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2003-01-28 at 18:10, Ivan Kokshaysky wrote: 
> Here's the patch that converts vgacon.c to pci_request_legacy_resource().
> Tested on i386 and a single-bus alpha (alpha specific bits not included
> here).
> 
> Note that it breaks ppc, as VGA_MAP_MEM() is removed...

Ok, if I understand properly, all we have to do on PPC is to implement a
pci_request_legacy_resource() that will do the right thing for legacy
VGA memory as well ?

Then, please, check the return value of pci_request_legacy_resource()
for getting to the VGA memory. Some machines (typically PowerMacs)
simply don't give you a way to generate PCI cycles to those low memory
addresses (you can't do VGA on those).

Disabling VGA dynamically depending on the machine have been a real pain
until now. With that change, it will now just be a matter for our PPC
implementation of pci_request_legacy_resource() to fail on machines
where VGA memory can't be reached.

Ben.