On 2015/3/17 13:59, Jon Masters wrote: > On 03/17/2015 12:10 AM, Hanjun Guo wrote: >> On 2015/3/17 11:23, Rafael J. Wysocki wrote: >>> On Tuesday, March 17, 2015 10:36:47 AM Hanjun Guo wrote: >>> Well, almost. There is one problem with that, becuase sleep.c contains code >>> outside of the ACPI_SLEEP-dependent blocks. That code is used for powering >>> off ACPI platforms. >>> >>> I guess you don't want that code on ARM too, right? >> Yes, you are right. >>> Perhaps we can use ACPI_REDUCED_HARDWARE_ONLY for that? ARM64 will be the >> Sorry, I can't fully understand your intention here, could you please >> explain it more? >> >> Let me guess a little bit. Do you mean use ACPI_REDUCED_HARDWARE_ONLY for >> powering off ACPI platforms? if so, I guess it's not a good idea, ACPI spec >> only says that S4BIOS is not supported on HW-reduced ACPI platforms, S5 >> has no such limitation, if I miss something here, please let me know. > If helpful to the discussion, current SBBR (Server Base Boot > Requirements[0]) design guidance is that for power off itself, we will > prefer calling an EFI Runtime Service (that will preferentially call an > PSCI - ARM Power State Coordination Interface - Secure Monitor Call (SMC > - think SMI-like) internally to perform the shutdown/reboot) for the > action of powering off or resetting 64-bit ARM SBBR platforms. Agreed, PSCI is the prefer method for power off on ARM64 I think. > > Therefore if the alternative of an ACPI-based power off solution were > not initially supported, I don't think it would have much practical > impact, and it could be addressed after the initial support merged. I agree. Actually we already removed ACPI power off code for ARM64 in v9 and v10 regardless the ACPI sepc statement about S5, I just want to confirm with Rafael that how to use ACPI_REDUCED_HARDWARE_ONLY properly to do the same thing as we do in v10 (patch - ACPI / sleep: Introduce CONFIG_ACPI_GENERIC_SLEEP), or if we have some other way to do that :) Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
