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

From: Geert Uytterhoeven (geert@linux-m68k.org)
Date: Tue Jan 28 2003 - 04:32:53 EST


On Tue, 28 Jan 2003, Ivan Kokshaysky wrote:
> On Mon, Jan 27, 2003 at 06:55:04PM +0100, Benjamin Herrenschmidt wrote:
> > Well, your example clearly limits us to one IO space for VGA, which
> > might not be what we want. The problem also exist for some fbdev drivers
> > which might need to tap the VGA IOs of a given PCI card (thus getting
> > access to the "legacy" IOs of the bus the card is on).
>
> You are right, I've already realized that. :-)
> The struct pci_bus * arg to legacy_ioport_remap (maybe better
> pci_legacy_ioport_remap) is really good idea, and it's perfectly
> ok to pass NULL in the vgacon case - we are limited to only one
> VGA console anyway.
> After the PCI setup is done, pci_legacy_ioport_remap(pbus, &legacy_resource)
> would solve any problem I can think of, including multiple ISA bridges.

BTW, we still need a separate isa_request_mem_region(), since right now we
cannot simply call request_mem_region(0xa0000, 0x10000) to request the VGA
memory buffer in ISA memory space. On ia32 the plain request_mem_region() is
OK, but on other archs you need to add the ISA memory space base.

Gr{oetje,eeting}s,

                                                Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds

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