Hi Matt, > -----Original Message----- > From: linux-pm-owner@xxxxxxxxxxxxxxx [mailto:linux-pm- > owner@xxxxxxxxxxxxxxx] On Behalf Of Matt Fleming > Sent: Friday, March 04, 2016 9:33 PM > To: Chen, Yu C > Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-efi@xxxxxxxxxxxxxxx; linux- > pm@xxxxxxxxxxxxxxx; rjw@xxxxxxx; lenb@xxxxxxxxxx; tglx@xxxxxxxxxxxxx; > x86@xxxxxxxxxx; Zhang, Rui; Zheng, Lv > Subject: Re: [PATCH][RFC] ACPI / PM: Fix poweroff issue on HW-full > platforms without _S5 > > On Wed, 02 Mar, at 09:29:17PM, 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. > > That should handle both the HW reduced mode, and the HW-full mode > > where the DSDT fails to supply an _S5 object. > > > > This patch fixes this issue by introducing a new flag acpi_no_s5 which > > indicates the non-existence of _S5. The initial state of acpi_no_s5 is > > false and probed in acpi_sleep_init, then we'll later see the updated > > value in efi_poweroff_required, according to which we can set > > pm_power_off to efi_power_off in efi_shutdown_init. > > > > Suggested-by: Len Brown <len.brown@xxxxxxxxx> > > Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx> > > --- > > arch/x86/platform/efi/quirks.c | 3 ++- > > drivers/acpi/sleep.c | 2 ++ > > include/acpi/acpixf.h | 6 ++++++ > > 3 files changed, 10 insertions(+), 1 deletion(-) > > Are there legacy platforms without _S5 where we currently handle reboot > via some other means that are going to break if we attempt an EFI reboot? > > I ask because historically performing an EFI reboot has been all kinds of buggy > on x86. I made a double check and yes there are other components would like to register their customized pm_power_off if _S5 is not available. So if EFI reboot is not stable, current code may not be robust enough . Hum, how about this one? (assigned to efi reboot only when there is no other components registered pm_power_off) return acpi_gbl_reduced_hardware || (acpi_no_s5 && ! pm_power_off); > > Also, is this what Windows does if _S5 is absent? I'm not sure, Windows might also leverage other drivers to achieve a poweroff. 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
