Re: [linux-pm] [PATCH 4/4] ACPI hibernate: Introduce new kernel parameter acpi_sleep=s4_nonvs

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Thursday, 23 of October 2008, Nigel Cunningham wrote:
> Hi.
> 
> On Wed, 2008-10-22 at 22:54 +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> > 
> > ACPI hibernate: Introduce new kernel parameter acpi_sleep=s4_nonvs
> > 
> > On some machines it may be necessary to disable the saving/restoring
> > of the ACPI NVS memory region during hibernation/resume.  For this
> > purpose, introduce new ACPI kernel command line option
> > acpi_sleep=s4_nonvs.
> > 
> > Based on a patch by Zhang Rui.
> > 
> > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > Cc: Zhang Rui <rui.zhang@intel.com>
> > ---
> >  Documentation/kernel-parameters.txt |    5 ++++-
> >  arch/x86/kernel/acpi/sleep.c        |    2 ++
> >  drivers/acpi/sleep/main.c           |   19 +++++++++++++++++--
> >  include/linux/acpi.h                |    1 +
> >  4 files changed, 24 insertions(+), 3 deletions(-)
> > 
> > Index: linux-2.6/Documentation/kernel-parameters.txt
> > ===================================================================
> > --- linux-2.6.orig/Documentation/kernel-parameters.txt
> > +++ linux-2.6/Documentation/kernel-parameters.txt
> > @@ -149,7 +149,8 @@ and is between 256 and 4096 characters. 
> >  			default: 0
> >  
> >  	acpi_sleep=	[HW,ACPI] Sleep options
> > -			Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
> > +			Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
> > +				  old_ordering, s4_nonvs }
> >  			See Documentation/power/video.txt for s3_bios and s3_mode.
> >  			s3_beep is for debugging; it makes the PC's speaker beep
> >  			as soon as the kernel's real-mode entry point is called.
> > @@ -159,6 +160,8 @@ and is between 256 and 4096 characters. 
> >  			control method, wrt putting devices into low power
> >  			states, to be enforced (the ACPI 2.0 ordering of _PTS is
> >  			used by default).
> > +			s4_nonvs prevents the kernel from saving/restoring the
> > +			ACPI NVS memory during hibernation.
> >  
> >  	acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
> >  			Format: { level | edge | high | low }
> > Index: linux-2.6/arch/x86/kernel/acpi/sleep.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/kernel/acpi/sleep.c
> > +++ linux-2.6/arch/x86/kernel/acpi/sleep.c
> > @@ -161,6 +161,8 @@ static int __init acpi_sleep_setup(char 
> >  #endif
> >  		if (strncmp(str, "old_ordering", 12) == 0)
> >  			acpi_old_suspend_ordering();
> > +		if (strncmp(str, "s4_nonvs", 13) == 0)
> 
> s/13/8/

Sure, thanks for catching that (it was a different string in the original
patch).

> > +			acpi_s4_no_nvs();
> >  		str = strchr(str, ',');
> >  		if (str != NULL)
> >  			str += strspn(str, ", \t");
> > Index: linux-2.6/drivers/acpi/sleep/main.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/acpi/sleep/main.c
> > +++ linux-2.6/drivers/acpi/sleep/main.c
> > @@ -59,6 +59,20 @@ void __init acpi_old_suspend_ordering(vo
> >  	old_suspend_ordering = true;
> >  }
> >  
> > +/*
> > + * The ACPI specification wants us to save NVS memory regions during hibernation
> > + * and to restore them during the subsequent resume.  However, it is not certain
> > + * if this mechanism is going to work on all machines, so we allow the user to
> > + * disable this mechanism using the 'acpi_sleep=s4_nonvs' kernel command line
> > + * option.
> > + */
> > +static bool s4_no_nvs;
> > +
> > +void __init acpi_s4_no_nvs(void)
> > +{
> > +	s4_no_nvs = true;
> > +}
> > +
> >  /**
> >   *	acpi_pm_disable_gpes - Disable the GPEs.
> >   */
> > @@ -323,7 +337,7 @@ static int acpi_hibernation_begin(void)
> >  {
> >  	int error;
> >  
> > -	error = hibernate_nvs_alloc();
> > +	error = s4_no_nvs ? 0 : hibernate_nvs_alloc();
> >  	if (!error)
> >  		acpi_target_sleep_state = ACPI_STATE_S4;
> >  
> > @@ -411,7 +425,8 @@ static int acpi_hibernation_begin_old(vo
> >  	int error = acpi_sleep_prepare(ACPI_STATE_S4);
> >  
> >  	if (!error) {
> > -		error = hibernate_nvs_alloc();
> > +		if (!s4_no_nvs)
> > +			error = hibernate_nvs_alloc();
> >  		if (!error)
> >  			acpi_target_sleep_state = ACPI_STATE_S4;
> >  	}
> > Index: linux-2.6/include/linux/acpi.h
> > ===================================================================
> > --- linux-2.6.orig/include/linux/acpi.h
> > +++ linux-2.6/include/linux/acpi.h
> > @@ -238,6 +238,7 @@ int acpi_check_mem_region(resource_size_
> >  #ifdef CONFIG_PM_SLEEP
> >  void __init acpi_no_s4_hw_signature(void);
> >  void __init acpi_old_suspend_ordering(void);
> > +void __init acpi_s4_no_nvs(void);
> >  #endif /* CONFIG_PM_SLEEP */
> >  #else	/* CONFIG_ACPI */
> 
> Apart from the above,
> 
> Acked-by: Nigel Cunningham <nigel@tuxonice.net>

Thanks,
Rafael