Re: [PATCH] ACPI: introduce kernel parameter acpi_sleep=s3_set_sci_en

[Zhang Rui <rui.zhang@intel.com>]

On Tue, 2009-10-27 at 16:21 +0800, Rafael J. Wysocki wrote:
> On Tuesday 27 October 2009, Zhang Rui wrote:
> > Introduce kernel parameter acpi_sleep=s3_set_sci_en
> > 
> > some laptop requires SCI_EN being set directly on resume,
> > or else they hung somewhere in the resume code path.
> > 
> > We already have a blacklist for these lattops but we still need
> > this option, especially when debugging some suspend/resume problems,
> > in case there are systems that need this workaround and are not yet
> > in the blacklist.
> > 
> > Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> 
> I'm generally fine with this, but ...
> 
> > ---
> >  Documentation/kernel-parameters.txt |    5 ++++-
> >  arch/x86/kernel/acpi/sleep.c        |    4 ++++
> >  drivers/acpi/sleep.c                |    6 ++++++
> >  include/linux/acpi.h                |    3 +++
> >  4 files changed, 17 insertions(+), 1 deletion(-)
> > 
> > Index: linux-2.6/drivers/acpi/sleep.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/acpi/sleep.c
> > +++ linux-2.6/drivers/acpi/sleep.c
> > @@ -182,6 +182,12 @@ static void acpi_pm_end(void)
> >   */
> >  static bool set_sci_en_on_resume;
> >  
> > +void __init acpi_set_sci_en_on_resume(void)
> > +{
> > +	set_sci_en_on_resume = true;
> > +	return 0;
> > +}
> > +
> >  extern void do_suspend_lowlevel(void);
> >  
> >  static u32 acpi_suspend_states[] = {
> > 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
> > @@ -162,6 +162,10 @@ static int __init acpi_sleep_setup(char 
> >  #endif
> >  		if (strncmp(str, "old_ordering", 12) == 0)
> >  			acpi_old_suspend_ordering();
> > +#ifdef CONFIG_SUSPEND
> > +		if (strncmp(str, "s3_set_sci_en", 13) == 0)
> > +			acpi_set_sci_en_on_resume();
> > +#endif /* CONFIG_SUSPEND */
> 
> ... do we really need these #ifdefs?
> 

#ifdef CONFIG_SUSPEND
...
static bool set_sci_en_on_resume;
...
#endif /* CONFIG_SUSPEND */

Or else I have to move set_sci_en_on_resume out of this #ifdef.

both solutions are okay to me but I think the current one is cleaner.

thanks,
rui

> >  		str = strchr(str, ',');
> >  		if (str != NULL)
> >  			str += strspn(str, ", \t");
> > Index: linux-2.6/include/linux/acpi.h
> > ===================================================================
> > --- linux-2.6.orig/include/linux/acpi.h
> > +++ linux-2.6/include/linux/acpi.h
> > @@ -251,6 +251,9 @@ int acpi_check_mem_region(resource_size_
> >  void __init acpi_no_s4_hw_signature(void);
> >  void __init acpi_old_suspend_ordering(void);
> >  void __init acpi_s4_no_nvs(void);
> > +#ifdef CONFIG_SUSPEND
> > +void __init acpi_set_sci_en_on_resume(void);
> > +#endif /* CONFIG_SUSPEND*/
> 
> s4_no_nvs is hibernation-specific, but it's not under a #ifdef.
> 
> >  #endif /* CONFIG_PM_SLEEP */
> >  
> >  #define OSC_QUERY_TYPE			0
> > Index: linux-2.6/Documentation/kernel-parameters.txt
> > ===================================================================
> > --- linux-2.6.orig/Documentation/kernel-parameters.txt
> > +++ linux-2.6/Documentation/kernel-parameters.txt
> > @@ -241,7 +241,7 @@ and is between 256 and 4096 characters. 
> >  
> >  	acpi_sleep=	[HW,ACPI] Sleep options
> >  			Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
> > -				  old_ordering, s4_nonvs }
> > +				  old_ordering, s4_nonvs, s3_set_sci_en }
> >  			See Documentation/power/video.txt for information on
> >  			s3_bios and s3_mode.
> >  			s3_beep is for debugging; it makes the PC's speaker beep
> > @@ -254,6 +254,9 @@ and is between 256 and 4096 characters. 
> >  			of _PTS is used by default).
> >  			s4_nonvs prevents the kernel from saving/restoring the
> >  			ACPI NVS memory during hibernation.
> > +			s3_set_sci_en causes the kernel to set SCI_EN directly
> > +			on resume from S3 (which is against the ACPI specification,
> > +			but some broken systems don't work without it).
> >  
> >  	acpi_use_timer_override [HW,ACPI]
> >  			Use timer override. For some broken Nvidia NF5 boards
> 
> Thanks,
> Rafael