2006-08-28 21:32:46

by john stultz

Subject: [PATCH -mm] Fix faulty HPET clocksource usage (fix for bug #7062)

Apparently some systems export valid HPET addresses, but hpet_enable()
fails. Then when the HPET clocksource starts up, it only checks for a
valid HPET address, and the result is a system where time does not
advance.

See http://bugme.osdl.org/show_bug.cgi?id=7062 for details.

This patch just makes sure we better check that the HPET is functional
before registering the HPET clocksource.

Signed-off-by: John Stultz <[email protected]>

diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
index c6737c3..17647a5 100644
--- a/arch/i386/kernel/hpet.c
+++ b/arch/i386/kernel/hpet.c
@@ -35,7 +35,7 @@ static int __init init_hpet_clocksource(
void __iomem* hpet_base;
u64 tmp;

- if (!hpet_address)
+ if (!is_hpet_enabled())
return -ENODEV;

/* calculate the hpet address: */

2006-08-28 21:39:35

by Andrew Morton

Subject: Re: [PATCH -mm] Fix faulty HPET clocksource usage (fix for bug #7062)

On Mon, 28 Aug 2006 14:32:39 -0700
john stultz <[email protected]> wrote:

> Apparently some systems export valid HPET addresses, but hpet_enable()
> fails. Then when the HPET clocksource starts up, it only checks for a
> valid HPET address, and the result is a system where time does not
> advance.
>
> See http://bugme.osdl.org/show_bug.cgi?id=7062 for details.
>
> This patch just makes sure we better check that the HPET is functional
> before registering the HPET clocksource.
>
> Signed-off-by: John Stultz <[email protected]>
>
> diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
> index c6737c3..17647a5 100644
> --- a/arch/i386/kernel/hpet.c
> +++ b/arch/i386/kernel/hpet.c
> @@ -35,7 +35,7 @@ static int __init init_hpet_clocksource(
> void __iomem* hpet_base;
> u64 tmp;
>
> - if (!hpet_address)
> + if (!is_hpet_enabled())
> return -ENODEV;
>
> /* calculate the hpet address: */

Thanks. This would be a 2.6.18 thing, wouldn't it?

2006-08-28 21:57:38

by john stultz

Subject: Re: [PATCH -mm] Fix faulty HPET clocksource usage (fix for bug #7062)

On Mon, 2006-08-28 at 14:39 -0700, Andrew Morton wrote:
> On Mon, 28 Aug 2006 14:32:39 -0700
> john stultz <[email protected]> wrote:
>
> > Apparently some systems export valid HPET addresses, but hpet_enable()
> > fails. Then when the HPET clocksource starts up, it only checks for a
> > valid HPET address, and the result is a system where time does not
> > advance.
> >
> > See http://bugme.osdl.org/show_bug.cgi?id=7062 for details.
> >
> > This patch just makes sure we better check that the HPET is functional
> > before registering the HPET clocksource.
> >
> > Signed-off-by: John Stultz <[email protected]>
> >
> > diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
> > index c6737c3..17647a5 100644
> > --- a/arch/i386/kernel/hpet.c
> > +++ b/arch/i386/kernel/hpet.c
> > @@ -35,7 +35,7 @@ static int __init init_hpet_clocksource(
> > void __iomem* hpet_base;
> > u64 tmp;
> >
> > - if (!hpet_address)
> > + if (!is_hpet_enabled())
> > return -ENODEV;
> >
> > /* calculate the hpet address: */
>
> Thanks. This would be a 2.6.18 thing, wouldn't it?

I would think so.

thanks
-john