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

[Andriy Gapon]

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.

-- 
Andriy Gapon