Re: [PATCH] PCI/ASPM: Clarify that pcie_aspm=off means leave ASPM untouched

From: Bjorn Helgaas
Date: Fri May 03 2024 - 12:47:06 EST


On Mon, Apr 29, 2024 at 02:18:21PM -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> Previously we claimed "pcie_aspm=off" meant that ASPM would be disabled,
> which is wrong.
>
> Correct this to say that with "pcie_aspm=off", Linux doesn't touch any ASPM
> configuration at all. ASPM may have been enabled by firmware, and that
> will be left unchanged. See "aspm_support_enabled".
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Applied with David's Reviewed-by to for-linus for v6.9, thanks, David!

> ---
> Documentation/admin-guide/kernel-parameters.txt | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index bb884c14b2f6..4bc281d6e8d3 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4590,9 +4590,10 @@
> norid [S390] ignore the RID field and force use of
> one PCI domain per PCI function
>
> - pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
> + pcie_aspm= [PCIE] Forcibly enable or ignore PCIe Active State Power
> Management.
> - off Disable ASPM.
> + off Don't touch ASPM configuration at all. Leave any
> + configuration done by firmware unchanged.
> force Enable ASPM even on devices that claim not to support it.
> WARNING: Forcing ASPM on may cause system lockups.
>
> --
> 2.34.1
>