From: george anzinger <george@mvista.com>
To: Vojtech Pavlik <vojtech@suse.cz>
Cc: Bjorn Helgaas <bjorn_helgaas@hp.com>,
Marcelo Tosatti <marcelo@conectiva.com.br>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] joydev: fix HZ->millisecond transformation
Date: Fri, 20 Dec 2002 09:24:58 -0800 [thread overview]
Message-ID: <3E03526A.2AA4B685@mvista.com> (raw)
In-Reply-To: 20021220142443.A26184@ucw.cz
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?
>
> 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....
>
> --
> Vojtech Pavlik
> SuSE Labs
> -
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--
George Anzinger george@mvista.com
High-res-timers:
http://sourceforge.net/projects/high-res-timers/
Preemption patch:
http://www.kernel.org/pub/linux/kernel/people/rml
next prev parent reply other threads:[~2002-12-20 17:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-16 19:27 [PATCH] joydev: fix HZ->millisecond transformation Bjorn Helgaas
2002-12-20 10:41 ` george anzinger
2002-12-20 13:24 ` Vojtech Pavlik
2002-12-20 14:52 ` Joe Korty
2002-12-20 17:24 ` george anzinger [this message]
2002-12-20 17:35 ` Vojtech Pavlik
2002-12-20 18:16 ` george anzinger
2002-12-21 9:18 ` Vojtech Pavlik
2002-12-21 16:46 ` george anzinger
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