From: Brian Julin <bri@forcade.calyx.net>
  To  : ggi-develop@eskimo.com
  Date: Mon, 10 Aug 1998 19:56:32 -0400 (EDT)

Re: kgicon problems...

On Mon, 10 Aug 1998, Rodolphe Ortalo wrote:
> In my case, mode->fb is filled with the "baseptr" field of the
> memory region containing the framebuffer. (I think it's a virtual
> address ?)

If it's i386 and it is of form 0xc####### then it is already
a virtual address.

> baseptr is initialized by mem_claim_region (kgicon/include/system.h)
> as ioremap(region->base, r->size).

I think your driver is written correctly then.  VGA is not, it
sets mode.fb to 0xa0000 explicitly.

> My guess: because ioremap returns a bus adress...
> 
> Am I right ?

Don't think so... Lemme refresh my memory... no it returns
phys_to_virt for the ISA bus "Hi Memory" range, null if you
try to remap anything between that and the end of physical 
RAM (thus prohibiting "windows"... bleh.), and a newly allocated
virtual address range for anything above the end of physical ram;
unless you try to map past/through the end of the processor's 
virtual address space in which case you get NULL.

> (Sorry for bothering you, but I always wondered what
> I should put there, or what I was putting there... ;-)

ioremap is best.  VGA driver text16 functions only use bus_to_virt
because the driver knows the VGA can only be in "Hi Memory".

--
Brian S. Julin