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

Ingo Molnar
2008-01-16T20:26:15Z

* Andreas Herrmann <andreas.herrmann3@amd.com> wrote:

> I just want to report that the PAT support in x86/mm causes crashes on
> two of my test machines. On both boxes the SATA detection does not
> work when the PAT support is patched into the kernel.
>
> Symptoms are as follows -- best described by a diff between the two
> boot.logs:
>
> # diff boot-failing.log boot-working.log
>
> -Linux version 2.6.24-rc8-ga9f7faa5 (root@hunter) (gcc version ...
> +Linux version 2.6.24-rc8-g2ea3cf43 (root@hunter) (gcc version ...
> ...
> early_iounmap(ffffffff82a0b000, 00001000)
> -early_ioremap(000000000000c000, 00001000) => -000002103394304
> -early_iounmap(ffffffff82a0c000, 00001000)

hm, so the early_ioremap() stuff isnt working well enough ...

that's the main effect of the PAT patches at the moment: no kernel code
will access the low linear mappings (BIOS tables, ACPI data, etc.)
directly, it's all done via early_ioremap(). But it's apparently buggy
somewhere ...

Ingo