Re: [PATCH]: ACPI: Skip the power state check in power transition

[yakui_zhao <yakui.zhao@intel.com>]

On Tue, 2009-05-12 at 22:57 +0800, Bjorn Helgaas wrote:
> On Monday 11 May 2009 11:27:40 pm yakui_zhao wrote:
> > From: Zhao Yakui <yakui.zhao@intel.com>
> > 
> > Skip the power state check in course of power transition by changing the
> > default value of acpi_power_nocheck to 1. If so, it is unnecessary to add the
> > boot option of "acpi.power_nocheck=1" or add it into DMI power check table to
> > skip the power state check.
> > 
> > Of course the power state check still can be enabled by adding the boot option
> > of "acpi.power_nocheck=0".
> 
> What is the value of keeping the "acpi.power_nocheck" option at all?
> 
> If we can get along without it, it'd be nice to just remove the
> whole thing.
Yes. If we delete the course of the power state check in power
transition, it will be unnecessary to add the boot option.

In fact this object is defined in ACPI spec. And we had better follow
that. IMO Linux ACPI does the right thing.
The boot option of "acpi.power_nocheck" is only to make Linux be
compatible with windows.

At the same time if we want to make the power state check more strict,
we will have to re-add the source-code. 

So IMO it will be better that the power state check in power transition
is controlled by one module parameter.

Best regards.
    Yakui.

> 
> Bjorn
> 
> > Index: linux-2.6/drivers/acpi/power.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/acpi/power.c	2009-04-16 16:10:24.000000000 +0800
> > +++ linux-2.6/drivers/acpi/power.c	2009-05-12 13:12:27.000000000 +0800
> > @@ -54,7 +54,7 @@
> >  #define ACPI_POWER_RESOURCE_STATE_ON	0x01
> >  #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
> >  
> > -int acpi_power_nocheck;
> > +int acpi_power_nocheck = 1;
> >  module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);
> >  
> >  static int acpi_power_add(struct acpi_device *device);
> > 
> > 
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> 
>