RE: [BK PATCH] acpismp=force fix

Hugh Dickins
2003-06-23T11:31:55Z

On Mon, 23 Jun 2003, Arjan van de Ven wrote:
> On Mon, 2003-06-23 at 09:43, Grover, Andrew wrote:
> > > From: Andrew Morton [mailto:akpm@digeo.com]
> > > > ACPI: make it so acpismp=force works (reported by Andrew Morton)
> >
> > > But prior to 2.5.72, CPU enumeration worked fine without
> > > acpismp=force.
> > > Now it is required. How come?
> >
> > (I'm taking the liberty to update the subject, which I accidentally left
> > blank)
> >
> > Because 2.4 has that behavior. One objection that people raised to
> > applying the 2.4 ACPI patch was that it changed that behavior. So I made
> > an effort to keep it there.
>
> in 2.4 it is absolutely not mantadory; it's default actually if the cpu
> advertises the "ht" flag.....

Right, enabling HT hasn't relied on "acpismp=force" since 2.4.18.
Requiring "acpismp=force" now in 2.4 or 2.5 is just a step backwards.

But when we changed to HT by default, I added bootparam "noht" to
disable it if it was found troublesome. Last time I checked, "noht"
was ineffectual on 2.5, and perhaps now it's ineffectual on 2.4.22-pre?

(If I remember right, in 2.5 it did have one effect, determining whether
the "ht" flag is shown in /proc/cpuinfo: but it was intended to be more
useful than that.)

Certainly reliance on "acpismp=force" should be removed if it's crept
back in. But what should we do about "noht"? Wave a fond goodbye,
and remove it's associated code and Documentation from 2.4 and 2.5
trees, rely on changing the BIOS setting instead? Or bring it back
into action?

Hugh