Re: ACPI "_PDC" - acpi_processor_set_pdc()- execution regression - Linux-3.x

From: Bjorn Helgaas
Date: Thu Dec 08 2011 - 00:01:49 EST


[+cc linux-acpi and Lin Ming]

On Wed, Dec 7, 2011 at 3:38 PM, <wallak@xxxxxxx> wrote:
> We have a regression on the ACPI stack of the last linux kernel line 3.x (3.1.4,
> 3.2-rc4...). The ACPI "_PDC" chunk is not executed on some computers (e.g. Dell
> X300; the function acpi_processor_set_pdc() is not called). This issue yield to
> an uninitialized state of some ACPI variables.
>
> A patch is available below. This patch come back to the previous linux behavior,
> and works fine.
>
> Best Regards,
> Wallak.
>
> --- linux-3.1.4-mdf/drivers/acpi/processor_core.c.orig  2011-12-07
> 23:12:57.000000000 +0100
> +++ linux-3.1.4-mdf/drivers/acpi/processor_core.c       2011-12-07
> 23:13:39.000000000 +0100
> @@ -223,8 +223,8 @@
>        type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
>        cpuid = acpi_get_cpuid(handle, type, acpi_id);
>
> -       if (cpuid == -1)
> -               return false;
> +       if ((cpuid == -1) && (num_possible_cpus() > 1))
> +               return false;
>
>        return true;
>  }
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/