Re: NetBSD Dom0 and (kind of) power management

[Jukka Ruohonen <jruohonen%iki.fi@localhost>]

On Fri, Mar 11, 2011 at 01:04:05AM +0100, Jean-Yves Migeon wrote:
> It needs ACPI work within NetBSD, oriented towards Xen. Most of the
> machinery currently used for x86 can be reused I think, the missing part
> being the code that will feed hypervisor with the information obtained
> via ACPI.

Can you outline the general problems involving ACPI and Xen? These issues
needs to be fixed sooner or later, given that the former is mandatory for
things like NUMA, etc.

In another thread:

> Power management under Xen requires ACPI support, as the hypervisor 
> does not implement extensive power management routines. Today's machines 
> requires ACPI parsing to query/obtain information regarding almost 
> everything, including PM, and this task is devoted to dom0. The support 
> is missing for NetBSD.

Looking at the Xen 4.0 sources, it contains Linux's in-kernel frequency
governor, among other things. So I guess it actually implements most of the
power management features available on Linux? But that seems to be closely
tied to the machine-dependent Linux drivers and APIs [1]. So I guess it is
likely that it will never work in NetBSD. Nor would it be desirable (or even
possible) to mimic Linux for the sake of Xen, IMO.

- Jukka.

[1] http://wiki.xensource.com/xenwiki/xenpm