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

[Nigel Cunningham]

Hi.

On Wed, 2008-10-22 at 22:54 +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw at 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 at sisk.pl>
> Cc: Zhang Rui <rui.zhang at 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/

> +			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 at tuxonice.net>