Re: [PATCH] PCI: Allow pcie_aspm=force to work even when FADTindicates it is unsupported

From: Andy Whitcroft
Date: Fri Mar 30 2012 - 05:55:40 EST


On Thu, Mar 22, 2012 at 4:49 PM, Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Right now using pcie_aspm=force will not enable ASPM if the FADT indicates
> ASPM is unsupported.  However, the semantics of force should probably allow
> for this, especially as they did before the ASPM disable rework with commit
> 3c076351c4027a56d5005a39a0b518a4ba393ce2
>
> This patch just skips the clearing of any ASPM setup that the firmware has
> carried out on this bus if pcie_aspm=force is being used.
>
> BugLink: https://bugs.launchpad.net/ubuntu/+bug/962038
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>  drivers/pci/pcie/aspm.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index 24f049e..e406429 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -783,6 +783,9 @@ void pcie_clear_aspm(struct pci_bus *bus)
>  {
>        struct pci_dev *child;
>
> +       if (aspm_force)
> +               return;
> +
>        /*
>         * Clear any ASPM setup that the firmware has carried out on this bus
>         */
> --
> 1.7.9.1

Andrew, I believe the above is also needed to fix some additional
regressions with the new ASPM code. If you are picking up the one
below this probably should go with it:

+ aspm-fix-pcie-devices-with-non-pcie-children.patch added to -mm tree

-apw
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