Re: [PATCH v3 1/2] x86, tsc: Fallback to normal calibration if fastMSR calibration fails

From: Ingo Molnar
Date: Sun Feb 09 2014 - 09:21:00 EST



* Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote:

> On Thu, Feb 06, 2014 at 03:34:18PM +0100, Thomas Gleixner wrote:
> > On Thu, 6 Feb 2014, Mika Westerberg wrote:
> > > arch/x86/kernel/tsc.c | 7 ++++---
> > > 1 file changed, 4 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
> > > index 19e5adb49a27..56facfc54575 100644
> > > --- a/arch/x86/kernel/tsc.c
> > > +++ b/arch/x86/kernel/tsc.c
> > > @@ -655,10 +655,11 @@ unsigned long native_calibrate_tsc(void)
> > > local_irq_save(flags);
> > > i = try_msr_calibrate_tsc(&fast_calibrate);
> > > local_irq_restore(flags);
> > > - if (i >= 0) {
> > > - if (i == 0)
> > > - pr_warn("Fast TSC calibration using MSR failed\n");
> > > + if (i > 0) {
> > > return fast_calibrate;
> > > + } else if (i == 0) {
> > > + pr_warn("Fast TSC calibration using MSR failed\n");
> > > + /* Continue with the normal calibration */
> > > }
> >
> > Bah. Can we please fix that proper. The whole 0,1,-1 return value from
> > try_msr_calibrate_tsc() is just horrible. Why not doing the obvious?
>
> Yes, that looks better and works fine, thanks.
>
> Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

Please resend the two updated/fixed patches in a new thread.

Thanks,

Ingo
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