On Tuesday, March 08, 2016 04:25:30 PM Chen, Yu C wrote: > > -----Original Message----- > > From: linux-pm-ow...@vger.kernel.org [mailto:linux-pm- > > ow...@vger.kernel.org] On Behalf Of Rafael J. Wysocki > > Sent: Tuesday, March 08, 2016 9:54 AM > > To: Chen, Yu C > > Cc: Rafael J. Wysocki; ACPI Devel Maling List; x...@kernel.org; linux- > > e...@vger.kernel.org; Linux Kernel Mailing List; linux...@vger.kernel.org; > > Len Brown; Matt Fleming; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; > > Zhang, Rui > > Subject: Re: [PATCH][RFC v3] ACPI / PM: Fix poweroff issue on HW-full > > platforms without _S5 > > > > On Monday, March 07, 2016 03:53:13 PM Chen, Yu C wrote: > > > Hi Rafael, > > > (resend for broken content) > > > > > > > -----Original Message----- > > > > From: rjwyso...@gmail.com [mailto:rjwyso...@gmail.com] On Behalf Of > > > > Rafael J. Wysocki > > > > Sent: Monday, March 07, 2016 9:19 PM > > > > To: Chen, Yu C > > > > Cc: ACPI Devel Maling List; x...@kernel.org; > > > > linux-...@vger.kernel.org; Linux Kernel Mailing List; > > > > linux...@vger.kernel.org; Rafael J. Wysocki; Len Brown; Matt > > > > Fleming; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; Zhang, Rui > > > > Subject: Re: [PATCH][RFC v3] ACPI / PM: Fix poweroff issue on > > > > HW-full platforms without _S5 > > > > > > > [cut] > > > > > bool efi_poweroff_required(void) > > > > > { > > > > > - return !!acpi_gbl_reduced_hardware; > > > > > + return acpi_gbl_reduced_hardware || (acpi_no_s5 && > > > > > + !pm_power_off); > > > > > > > > What if CONFIG_ACPI is not set here? > > > If CONFIG_ACPI is not set, this file would not be compiled, because > > > CONFIG_EFI depends on CONFIG_ACPI. > > > > OK > > > > So the next question will be if efi_poweroff_required() is guaranteed to run > > after all of the other code that may register alternative power off > > handling. > Hum. unfortunately it is not guaranteed to run after all of the other code, > because other components who register pm_power_off may be built as modules, > and > we can not predict/control the sequence registration. So this patch may > break the EFI platforms who use non-efi poweroff due to unstable EFI service > , not sure if there are any released-products of this kind. > > Currently I'm thinking of 3 possible solutions, could you please give some > advices on them: > > 1. Introduce bootopt of 'poweroff=efi' > Set the pm_power_off to efi_power_off no matter whether there is _S5 or > not > > 2. Introduce /sys/power/poweroff > Allow the user to choose which pm_power_off, for example: > > # cat /sys/power/poweroff > *acpi acpi_power_off > efi efi_power_off > gpio gpio_poweroff_do_poweroff > user can echo string to enable which one. > > And two APIs: > register_power_off(char *name, power_off func) > unregister_power_off(char *name) > > > 3. replace all the codes of pm_power_off() with reliable_pm_power_off() > > void reliable_pm_power_off(void) > { > if (!pm_power_off) { > if (acpi_no_s5) > pm_power_off = efi_power_off; > /* Other conditions added in the future. */ > } > pm_power_off(); > }
What about something like adding something like default_power_off that would be used by pm_power_off if nothing else is available? Thanks, Rafael
