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

[Andreas Herrmann3]

On Thu, Jan 17, 2008 at 10:13:08PM +0100, Ingo Molnar wrote:
> 
> * Andreas Herrmann3 <andreas.herrmann3@xxxxxxx> 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



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