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

[Mario Limonciello]

On 8/3/23 00:01, Mika Westerberg wrote:
> 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:
Are you sure?  I saw it as an explanation of how Windows could put the 
systems into D3 when there is no other PM related ACPI objects.

> - 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
>
> ?

Thanks! That sounds very reasonable to me.  I'll double check it in my case.