Re: [PATCH v8 2/2] PCI/ACPI: Use device constraints instead of dates to opt devices into D3

[Mika Westerberg]

Hi,

On Wed, Aug 02, 2023 at 03:10:13PM -0500, Mario Limonciello wrote:
> @@ -3036,11 +3044,8 @@ bool pci_bridge_d3_possible(struct pci_dev *bridge)
>  		if (dmi_check_system(bridge_d3_blacklist))
>  			return false;
>  
> -		/*
> -		 * It should be safe to put PCIe ports from 2015 or newer
> -		 * to D3.
> -		 */
> -		if (dmi_get_bios_year() >= 2015)
> +		/* the platform indicates in a device constraint that D3 is needed */
> +		if (platform_constraint_d3(bridge))

This for sure causes some sort of power regression on the Intel
platforms made after 2015. Why not check for the constraint and:

- If present and enabled, use the desired D-state
- If present and disabled, leave the device in D0
- If not present use the existing cutoff date

?