Russell King wrote:
> > I've noticed that one of my machines here suffers from the "time going
> > backwards problem" and so started thinking about the x86 solution.
> >
> > I've come to the conclusion that it has a hole which could cause it
> > to return the wrong time in one specific case:
> >
> > - in do_gettimeofday(), we disable irqs (read_lock_irqsave)
> > - the ISA timer wraps, but we've got interrupts disabled, so no update
> > of xtime or jiffies occurs
> > - in do_slow_gettimeoffset(), we read the timer, which has wrapped
> > - since jiffies_p != jiffies, we do not apply any correction
> > - our idea of time is now one jiffy slow.
>
> I never heard any response to this. Could some knowledgeable person please
> take a look at it?
do_slow_gettimeoffset() is supposed to correct for wrapping.
But where it says:
#define BUGGY_NEPTUN_TIMER
if( jiffies_t == jiffies_p ) {
if( count > count_p ) {
/* the nutcase */
Shouldn't that say "count < count_p"?
-- Jamie
-
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/
This archive was generated by hypermail 2b29 : Fri Mar 23 2001 - 21:00:12 EST