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

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

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

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@google.com>
---
 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

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

[David E. Box]

On Mon, 2024-04-29 at 14:18 -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> 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@google.com>

LGTM.

Reviewed-by: David E. Box <david.e.box@linux.intel.com>

> ---
>  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.
>  

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

[Bjorn Helgaas]

On Mon, Apr 29, 2024 at 02:18:21PM -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> 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@google.com>

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
>