Re: [PATCH] Revert "PCI/ASPM: Disable only ASPM_STATE_L1 when driver, disables L1"

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Oct 11, 2023 at 09:36:40AM +0200, Heiner Kallweit wrote:
> This reverts commit fb097dcd5a28c0a2325632405c76a66777a6bed9.
> 
> After the referenced commit we may see L1 sub-states being active
> unexpectedly. Following scenario as an example:
> r8169 disables L1 because of known hardware issues on a number of
> systems. Implicitly L1.1 and L1.2 are disabled too.
> On my system L1 and L1.1 work fine, but L1.2 causes missed
> rx packets. Therefore I write 1 to aspm_l1_1.
> This removes ASPM_STATE_L1 from the disabled modes and therefore
> unexpectedly enables also L1.2. So return to the old behavior.
> 
> Link: https://lore.kernel.org/linux-pci/20231002151452.GA560499@bhelgaas/
> Cc: stable@vger.kernel.org
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Applied to pci/aspm for v6.7, thanks, Heiner!

> ---
> Splitted the first version of the patch according to the linked discussion.
> ---
>  drivers/pci/pcie/aspm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index 1bf630059264..530c3bb5708c 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -1059,7 +1059,8 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
>  	if (state & PCIE_LINK_STATE_L0S)
>  		link->aspm_disable |= ASPM_STATE_L0S;
>  	if (state & PCIE_LINK_STATE_L1)
> -		link->aspm_disable |= ASPM_STATE_L1;
> +		/* L1 PM substates require L1 */
> +		link->aspm_disable |= ASPM_STATE_L1 | ASPM_STATE_L1SS;
>  	if (state & PCIE_LINK_STATE_L1_1)
>  		link->aspm_disable |= ASPM_STATE_L1_1;
>  	if (state & PCIE_LINK_STATE_L1_2)
> -- 
> 2.42.0
>