(Missing) power states of an Atom N455-based netbook

[Jung-uk Kim]

On Tuesday 28 June 2011 05:26 pm, Andriy Gapon wrote:
> on 28/06/2011 22:14 Jung-uk Kim said the following:
> > On Tuesday 28 June 2011 07:28 am, Andriy Gapon wrote:
> >> I think that part (but not all) of the differences between
> >> FreeBSD and Linux can be explained by the fact that FreeBSD
> >> currently doesn't advertise itself as featuring
> >> ACPI_CAP_SMP_C1_NATIVE and ACPI_CAP_SMP_C3_NATIVE.  I am not
> >> sure what it would take to actually support these features.  I
> >> think that Linux does support (or at least advertise support)
> >> for these features.
> >
> > Yes, Linux supports this Intel-specific feature.  I think it
> > shouldn't be too hard for us, however.  We just have to add
> > support for Intel-specific _CST FFH (Functional Fixed Hardware)
> > in
> > sys/dev/acpica/acpi_cpu.c.  You can find more information from
> > "Intel Processor Vendor-Specific ACPI" (order number 302223-005)
> > on Intel website.  Also, arch/x86/kernel/acpi/cstate.c of Linux
> > source may help.  I believe Linux actually supports all
> > Intel-specific FFHs, BTW.
>
> Once upon a time there was a patch proposed for FreeBSD:
> http://thread.gmane.org/gmane.os.freebsd.current/127860/focus=6372
> Unfortunately I have never really evaluated it.

Hmm, interesting patch.  I think he is in the right direction.

Thanks for sharing,

Jung-uk Kim