On Mon, Aug 21, 2023 at 9:18 PM Limonciello, Mario <mario.limonciello@xxxxxxx> 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@xxxxxxx> 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.
