Re: [git pull] PCI changes

From: Matthew Garrett
Date: Fri Jan 13 2012 - 16:24:20 EST


On Wed, Jan 11, 2012 at 07:38:25PM -0800, Linus Torvalds wrote:
> On Wed, Jan 11, 2012 at 10:34 AM, Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> wrote:
> >
> > Matthew Garrett (1):
> >      PCI: Rework ASPM disable code
>
> Yay.
>
> However, looking this through some more, I'm still a bit confused by
> the pcie_clear_aspm() call in acpi_pci_root_add().
>
> It seems to be explicitly against the rules elsewhere - we clear ASPM
> even though ACPI_FADT_NO_ASPM is set - which the changelog (and the
> other parts of that commit) says means "don't touch pre-existing ASPM
> state").
>
> So why is acpi_pci_root_add() special? Cna you explain that part to me?

pcie_no_aspm() means "Do not permit ASPM to be enabled" - it doesn't
alter the existing state. pcie_clear_aspm() does that.

--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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