Re: [Ubuntu PATCH] cpufreq: fix powernow-k8 load bug

Dave Jones
2006-06-23T12:29:03Z

On Thu, Jun 22, 2006 at 10:38:56PM +0200, Pavel Machek wrote:
> > --- linux-2617-pv.orig/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
> > +++ linux-2617-pv/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
> > @@ -1008,7 +1008,7 @@ static int __cpuinit powernowk8_cpu_init
> > * an UP version, and is deprecated by AMD.
> > */
> >
> > - if ((num_online_cpus() != 1) || (num_possible_cpus() != 1)) {
> > + if ((num_online_cpus() != 1)) {
> > printk(KERN_ERR PFX "MP systems not supported by PSB BIOS structure\n");
> > kfree(data);
> > return -ENODEV;
> >
>
> Seems wrong to me... what if I boot, then hotplug second cpu?

We only run this code if powernow_k8_cpu_init_acpi() has failed,
which it should never do on an SMP system.

So, you get exactly the same behaviour, as expected.
You can't support >1 CPU with PSB.

The above patch makes sure things continue to work if you run
an SMP kernel on UP hardware.