Messages in this thread | | | Date | Mon, 21 Aug 2023 14:26:22 -0500 | Subject | Re: [PATCH v14.c 4/4] PCI: ACPI: Limit the Intel specific opt-in to D3 to 2024 | From | "Limonciello, Mario" <> |
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On 8/21/2023 2:24 PM, Rafael J. Wysocki wrote: > On Mon, Aug 21, 2023 at 9:18 PM Limonciello, Mario > <mario.limonciello@amd.com> wrote: >> >> >> >> On 8/21/2023 1:46 PM, Rafael J. Wysocki wrote: >>> On Fri, Aug 18, 2023 at 9:40 PM Mario Limonciello >>> <mario.limonciello@amd.com> wrote: >>>> >>>> Intel systems that need to have PCIe ports in D3 for low power idle >>>> specify this by constraints on the ACPI PNP0D80 device. As this information >>>> is queried by acpi_pci_bridge_d3(), limit the DMI BIOS year check to stop >>>> at 2024. This will allow future systems to rely on the constraints check >>>> and ACPI checks to set up policy like non-Intel systems do. >>> >>> So I'm not sure about the value of this change. >>> >>> The behavior is made Intel-specific in [14a 1/1] and it will be that >>> way at least for some time. This change only sets the date after >>> which it won't be Intel-specific any more, but for what reason >>> exactly? >>> >>> And why is 2024 the cut-off year (and not 2025, for example)? >> >> No particular reason other than it's a few kernel cycles to get this >> tested and working or revert it if it's a bad idea after all. >> >>> >>> If Intel platforms continue to be OK with putting all PCIe ports into >>> D3hot beyond 2024, why restrict the kernel from doing so on them? >> >> OK let me try to explain my thought process. >> >> The reason that root ports were put into D3 on Intel systems was that >> it's required for the system to get into the deepest state. >> >> At the time that it was introduced there wasn't a way for the firmware >> to express this desire for root ports that were not power manageable by >> ACPI. >> >> Constraints are a good way to express it, so by limiting the Intel >> hardcode to a number of years gets everyone onto the same codepaths. > > Assuming that the will be used in future systems, but that is beyond > the control of anyone involved here I think. > >> But that being said - if you would rather keep Intel as hardcode forever >> this patch can be dropped from the series. > > This change can be made at any time and I don't see a particular > reason for making it right now.
OK, then after Bjorn reviews the other patches of 14.a and 14.c I'll drop this patch.
Thanks!
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