Re: [PATCH] Set bit 1 in disabled processor's _STA

Glauber Costa
2009-05-18T12:54:00Z

On Mon, May 18, 2009 at 03:42:10PM +0300, Gleb Natapov wrote:
> On Mon, May 18, 2009 at 09:40:03AM -0300, Glauber Costa wrote:
> > On Mon, May 18, 2009 at 02:40:18PM +0300, Gleb Natapov wrote:
> > > On Mon, May 18, 2009 at 08:39:43AM -0300, Glauber Costa wrote:
> > > > > Now I recall something on LKML about this. Well, in this case Linux
> > > > > shouldn't have used ACPI to invent its own way to do cpu hot-plug.
> > > > It didn't.
> > > > History shows that this method is what is used in some unisys machines,
> > > > which seems to be the only ones implementing this around.
> > > The questions are: What is "this" that linux currently implements, how
> > > windows expects CPU hot-plug to work, are there any real x86 hardware
> > > that supports CPU host-plug and what should we do about all this.
> > as I said, there are unisys machines that implements cpu hotplug.
> > The way they do it, is the way Linux kernel currently expects. The same way
> > we implement on our BIOS.
> I read that document too. And "based on some input from Natalie of Unisys"
> does not sound promising.
I'm not saying it is promising. Nothing un-specified is. Google search for the
mails exchanged on the time of development of this also point in the direction that
this is probably all we have.

> Are those Unisys machines certified to run
> Windows 2008? Because if they are, they surely do something different
> from what we are doing.
Unless they have a time machine, it is unlikely. Windows 2008 did not exist
at the time