Hi Matt, > -----Original Message----- > From: Matt Fleming [mailto:matt@xxxxxxxxxxxxxxxxxxx] > Sent: Friday, March 11, 2016 11:56 PM > To: Chen, Yu C > Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; Rafael J. Wysocki; > Len Brown; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; Zhang, Rui; linux- > efi@xxxxxxxxxxxxxxx; x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Ard > Biesheuvel; Mark Salter > Subject: Re: [PATCH][RFC,v4] ACPI / PM: Introduce efi poweroff for HW-full > platforms without _S5 > > On Fri, 11 Mar, at 05:05:33PM, Chen Yu wrote: > > The problem is Linux registers pm_power_off = efi_power_off only if we > > are in hardware reduced mode. Actually, what we also want is to do > > this when ACPI S5 is simply not supported on non-legacy platforms. > > That should handle both the HW reduced mode, and the HW-full mode > > where the DSDT fails to supply an _S5 object. > > > > This patch introduces pm_power_off_default which would be used by > > pm_power_off if nothing else is available. And in this case we > > leverage efi power off to be this role. However since efi power off > > may not be stable enough thus in order not to interfere with other > > poweroff path, we only make a minimum enhancement for x86 in > > native_machine_power_off. > > > > Suggested-by: Len Brown <len.brown@xxxxxxxxx> > > Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx> > > --- > > v4: > > - Since in v3 efi_poweroff_required() is not guaranteed to run > > after all of the other code that may register alternative > > power off handling, add the pm_power_off_default that would > > be used by pm_power_off if nothing else is available. > > v3: > > - Only assign pm_power_off to efi_power_off when there are no > > other pm_power_off registered at that time, in case other > > commponents would like to customize their own implementation. > > --- > > v2: > > - Convert the acpi_no_s5 to a global bool variable in sleep.c and > > add a declaration to include/linux/acpi.h. > > --- > > arch/x86/kernel/reboot.c | 3 +++ > > arch/x86/platform/efi/quirks.c | 5 +++++ > > drivers/acpi/sleep.c | 7 +++++++ > > drivers/firmware/efi/reboot.c | 8 ++++++++ > > include/linux/acpi.h | 1 + > > include/linux/efi.h | 1 + > > include/linux/pm.h | 1 + > > kernel/reboot.c | 1 + > > 8 files changed, 27 insertions(+) > > Couple of things, > > 1) I'm still waiting for an answer to my question on whether > platforms without _S5 that need EFI reset actually exist. You > said they "might" exist, which makes this all sound very > speculative. It is not obvious to me that this approach makes > sense. There is a future Base-IA platform, we are planning to skip implementing the SLP_TYP register and the S5 object. (already there will be no S3 and no S4) > > 2) In v4 you're modifying the generic EFI reboot code and should Cc > other developers who might care, e.g. the arm64 folks. I've Cc'd > them now. OK, thanks. yu -- 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
