Re: [patch 0/4] x86: PAT followup - Incremental changes and bug fixes

Andreas Herrmann3
2008-01-17T21:48:52Z

On Thu, Jan 17, 2008 at 10:13:08PM +0100, Ingo Molnar wrote:
>
> * Andreas Herrmann3 <andreas.herrmann3@amd.com> wrote:
>
> > Yes.
> >
> > Meanwhile I have figured out that it is some ACPI stuff that maps the
> > page cached. I've changed the ioremap's in drivers/acpi/osl.c to
> > ioremap_nocache. See attached patch.
> >
> > Now the machine boots without conflicts.
>
> ah, nice!
>
> but in general we must be robust enough in this case and just degrade
> any overlapping page to UC (and emit a warning perhaps) - instead of
> failing the ioremap and thus failing the driver (and the bootup).
>
> Does my third patch (which falls back to UC in case of attribute
> conflicts, also attached below) instead of your ioremap_nocache() patch
> solve your bootup problem too?

I'll check this asap

> but i have not seen this message in your boot log. Could you boot with
> early_ioremap_debug and send us the dmesg - i'm curious which ACPI
> tables are actively mapped while those devices are initialized.

Hmm, early_ioremap_debug exists only in ioremap_32.c
Have to adapt the 64-bit version first.

But wait the 64-bit code contains already debug output for this. See
the boot-logs that I have attached to my previous mails.
(Interestingly the code for 64-bit early_io(re/un)map resides not in
ioremap_64.c but in init_64.c.)

Andreas