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Message-ID: <06cf76ba-de5f-caaa-d1c4-9d34adf15a52@amd.com>
Date: Thu, 3 Aug 2023 06:38:45 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
Bjorn Helgaas <helgaas@...nel.org>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
Iain Lane <iain@...ngesquash.org.uk>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>
Subject: Re: [PATCH v8 2/2] PCI/ACPI: Use device constraints instead of dates
to opt devices into D3
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.
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