Re: [PATCH v3 0/7] ACPI: Add _OST support for ACPI hotplug

From: Toshi Kani
Date: Fri May 11 2012 - 13:27:25 EST

On Fri, 2012-05-11 at 10:09 -0700, Andi Kleen wrote:
> Toshi Kani <toshi.kani@xxxxxx> writes:
> > This patchset supports ACPI OSPM Status Indication (_OST) method for
> > ACPI CPU/memory/container hotplug operations and sysfs eject. After
> > ACPI hotplug operation has completed, OSPM calls _OST to indicate the
> > result of the operation to the platform. If _OST is not present, this
> > patchset has no effect on the platform.
> >
> > This _OST support can be enabled or disabled with a new config option
> > CONFIG_ACPI_HOTPLUG_OST. This option is disabled by default. When
> > this option is disabled, this patchset has no effect on the platform.
> Does that control compiling in/out significant sized code?
> Controlling code behaviour by CONFIG option has been long deprecated.
> This is always better done as a runtime option.
> Just think what should a distribution who wants to use the same binary
> on all systems set.

Good question. The OS needs to tell the platform if it supports _OST at
boot-time, and has to stick with it. Therefore, this feature may not be
enabled/disabled during run-time. Another reason is that this feature
config options in order to provide consistent behavior among multiple
hotplug operations with regarding the _OST support.


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