Re: [pm] fix time after suspend-to-*

[john stultz]

On Thu, 2003-10-23 at 16:09, George Anzinger wrote:
> john stultz wrote:
> > On Thu, 2003-10-23 at 13:23, George Anzinger wrote:
> >>I lost (never saw) the first of this thread, BUT, if this is 2.6, I strongly 
> >>recommend that settimeofday() NOT be called.  It will try to adjust 
> >>wall_to_motonoic, but, as this appears to be a correction for time lost while 
> >>sleeping, wall_to_monotonic should not change.
> > 
> > While suspended should the notion monotonic time be incrementing? If
> > we're not incrementing jiffies, then uptime isn't being incremented, so
> > to me it doesn't follow that the monotonic time should be incrementing
> > as well. 
> 
> Uh, not moving jiffies?  What does this say about any timers that may be 
> pending?  Say for cron or some such?  Like I said, I picked up this thread a bit 
> late, but, seems to me that if time is passing, it should pass on both the 
> jiffies AND the wall clocks.

My understanding is that we are suspending the box (ie: putting your
laptop to sleep/hybernate), so for all practical purposes the box is off
waiting until it is woken up. During that time I don't believe we
receive timer interrupts. When we are woken up, we should update the
system time and continue, but as the box wasn't running during the
interim we shouldn't be increasing the notion of monotonic time. 

> > It may very well be a POSIX timers spec issue, but it just strikes me as
> > odd.
> 
> The spec thing would relate to any sleeps or timers that are pending.  The spec 
> would seem to say they should complete somewhere near the requested wall time, 
> but NEVER before.  By not moving jiffies, I think they will be a bit late.  Now, 
> if they were to complete during the sleep, well those should fire at completion 
> of the sleep.  If the are to complete after the sleep, then, it seems to me, 
> they should fire at the requested time.

Hmmm. That last sentence gives me pause. I guess it comes down to how
you request your timer expiration: in wall time or system time.  I
always thought it was in system time, but you know this stuff better
then I, so I'll defer.

Pavel: You new patch looks ok wrt the locking issue. I'm still pretty
suspicious of the clock_cmos_diff but I'll trust you that it does the
right thing (this has been tested, right? :)

thanks
-john

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/