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SubjectRe: [PATCH] Re: time() glitch on 2.4.18: solved
Jim Paris wrote:
>
> > > Any comments?
> >
> > Have a play with it, if your idea works when you deliberately disturb it
> > then send in a patch
>
> This works well.

But it does introduce a hiccup in time. One could just do
an odd read IF that is all that is wrong. Your code could
also be correcting for other ills...

-g
>
> -jim
>
> diff -urN linux-2.4.18/arch/i386/kernel/time.c linux-2.4.18-jim/arch/i386/kernel/time.c
> --- linux-2.4.18/arch/i386/kernel/time.c Fri Mar 15 18:28:53 2002
> +++ linux-2.4.18-jim/arch/i386/kernel/time.c Tue Nov 5 11:22:02 2002
> @@ -501,6 +501,16 @@
>
> count = inb_p(0x40); /* read the latched count */
> count |= inb(0x40) << 8;
> +
> + /* Any unpaired read will cause the above to swap MSB/LSB
> + forever. Try to detect this and reset the counter. */
> + if (count > LATCH) {
> + outb_p(0x34, 0x43);
> + outb_p(LATCH & 0xff, 0x40);
> + outb(LATCH >> 8, 0x40);
> + count = LATCH - 1;
> + }
> +
> spin_unlock(&i8253_lock);
>
> count = ((LATCH-1) - count) * TICK_SIZE;
> -
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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
-
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