Messages in this thread | | | Date | Fri, 20 Dec 2002 18:35:44 +0100 | From | Vojtech Pavlik <> | Subject | Re: [PATCH] joydev: fix HZ->millisecond transformation |
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On Fri, Dec 20, 2002 at 09:24:58AM -0800, george anzinger wrote: > Vojtech Pavlik wrote: > > > > On Fri, Dec 20, 2002 at 02:41:50AM -0800, george anzinger wrote: > > > Bjorn Helgaas wrote: > > > > > > > > * fix a problem with HZ->millisecond transformation on > > > > non-x86 archs (from 2.5 change by vojtech@suse.cz) > > > > > > > > Applies to 2.4.20. > > > > > > > > diff -Nru a/drivers/input/joydev.c b/drivers/input/joydev.c > > > > --- a/drivers/input/joydev.c Mon Dec 16 12:16:32 2002 > > > > +++ b/drivers/input/joydev.c Mon Dec 16 12:16:32 2002 > > > > @@ -50,6 +50,8 @@ > > > > #define JOYDEV_MINORS 32 > > > > #define JOYDEV_BUFFER_SIZE 64 > > > > > > > > +#define MSECS(t) (1000 * ((t) / HZ) + 1000 * ((t) % HZ) / HZ) > > > Uh... > > > ^^^^^^^^^^^^^^^^ > > > by definition this is zero, is it not? > > > > No, both parts of the equaition can be nonzero. > > I don't think so. s%HZ has to be less than HZ. Then > dividing that by HZ should result in zero. Where is my > thinking flawed?
You first multiply it by 1000.
> > Though it might be easier to say (1000 * t) / HZ, now that I think about > > it. > > That overflows... As does the other if HZ is less than 1000....
You're right, t can be all 32 bits.
-- Vojtech Pavlik SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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