Re: [PATCH v13 01/12] PCI: Only put Intel PCIe ports >= 2015 into D3

[Kuppuswamy Sathyanarayanan]

Hi,

On 8/17/2023 10:13 PM, Mario Limonciello wrote:
> commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> changed pci_bridge_d3_possible() so that any vendor's PCIe ports
> from modern machines (>=2015) are allowed to be put into D3.
> 
> Iain reports that USB devices can't be used to wake a Lenovo Z13
> from suspend. This is because the PCIe root port has been put
> into D3 and AMD's platform can't handle USB devices waking in this
> case.
> 
> This behavior is only reported on Linux. Comparing the behavior
> on Windows and Linux, Windows doesn't put the root ports into D3.
> 
> To fix the issue without regressing existing Intel systems,
> limit the >=2015 check to only apply to Intel PCIe ports.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> Reported-by: Iain Lane <iain@xxxxxxxxxxxxxxxxxxx>
> Closes: https://forums.lenovo.com/t5/Ubuntu/Z13-can-t-resume-from-suspend-with-external-USB-keyboard/m-p/5217121
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---

Looks good to me.

Reviewed-by:Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

> v12->v13:
>  * New patch
> ---
>  drivers/pci/pci.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 60230da957e0c..051e88ee64c63 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3037,10 +3037,11 @@ bool pci_bridge_d3_possible(struct pci_dev *bridge)
>  			return false;
>  
>  		/*
> -		 * It should be safe to put PCIe ports from 2015 or newer
> +		 * It is safe to put Intel PCIe ports from 2015 or newer
>  		 * to D3.
>  		 */
> -		if (dmi_get_bios_year() >= 2015)
> +		if (bridge->vendor == PCI_VENDOR_ID_INTEL &&
> +		    dmi_get_bios_year() >= 2015)
>  			return true;
>  		break;
>  	}

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer