Re: [PATCH] set altix preferred console

Mark Maule
2005-10-04T15:04:28Z

On Mon, Oct 03, 2005 at 09:44:08AM -0500, Greg Edwards wrote:
> On Fri, Sep 30, 2005 at 03:20:11PM -0600, Bjorn Helgaas wrote:
> | I think what *should* happen is that we should discover VGA
> | devices by PCI enumeration, and the iobase/membase information
> | would come from the ACPI description of the PCI root bridges.
> | Then we could support multiple VGA devices, and the PCDP could
> | point to one of them to be used as the console.
> |
> | The VGA code in the kernel is a long ways from that. But your
> | firmware should provide the vga_console_{iobase,membase} data
> | somewhere besides the PCDP. Can you do something in ia64/sn
> | to dig it out?
>
> Thanks for the info and suggestion, Bjorn. I think we should be able to
> come up with something in sn-specific code. I'll talk to our I/O guys
> and see what we can come up with.
>
> Greg

Our prom currently does not build up ACPI tables describing PCI (or any IO)
devices. We are working toward that goal, but it is still
work in progress and will be some time yet before this is done.

It is because of this shortcoming that we have to rely on the PCDP table
to provide the io addresses needed for VGA console.

Outside of PCDP, our earliest opportunity to get information about VGA
devices is through the call sequence initiated with
subsys_initcall(sn_pci_init), which would seem way too late for early boot
messages.

Out of curiousity, what are the mmio_tra/ioport_tra fields in the PCDP PCI
interface structure intended for if not for this purpose?

Mark