From: Pavel Machek <pavel@ucw.cz>
To: Bernard Blackham <bernard@blackham.com.au>
Cc: Shaw <shawv@comcast.net>, linux-kernel@vger.kernel.org
Subject: Re: Screwy clock after apm suspend
Date: Tue, 11 Jan 2005 01:14:26 +0100 [thread overview]
Message-ID: <20050111001426.GF1444@elf.ucw.cz> (raw)
In-Reply-To: <20050110174804.GC4641@blackham.com.au>
Hi!
> > > > > arch/i386/kernel/time.c, can you comment out
> > > > > jiffies += sleep_length * HZ;
> > > >
> > > > Worked like a charm. I'm not seeing any time drift after your suggested
> > > > change.
> > >
> > > AIUI, this also means that a machine's uptime does not include time
> > > whilst suspended. This was the behaviour prior to 2.6.10 and seems to be
> > > more desirable as it counts the time the machine is actually running,
> > > not just time since boot. Is there a good reason why we can't go back to
> > > this?
> >
> > I think it means very wrong system clock in ACPI state.
>
> So would implementing the equivalent of hwclock --hctosys keep both
> ACPI & APM happy, but not include time suspended in uptime?
I think that hwclock --hctosys is not quite straightforward operation
-- it needs to know if your CMOS clock are in local timezone or GMT,
or something like that, IIRC.
But this might work: compute difference between system and cmos time
before suspend, and use that info to restore time after suspend.
> > Plus think something wanting timeout of five minutes, then suspend
> > one minute after, machine sleeps for a hour.
> >
> > With this approach, timeout should happen just after resume, with your
> > approach, it would wait 4 more minutes.
>
> It does depend on whether a timer wants a delay against the wall
> clock or the rest of the system. A process may be sleeping because
> it's waiting for some other task to complete, or waiting for input
> from the user. In these cases I claim time-whilst-hibernated should
> not be counted.
> Hibernating shouldn't be noticeable to the system. For example, a
> popup window that came up an instant prior to suspending which is
> normally on the screen for several seconds would vanish instantly
> upon resuming without the user ever seeing it.
I disagree here.
If I do cli(); sleep(5 hours); sti();, system should survive that. If
you do cli(); sleep(5 hours); sti() but fail to compensate for lost
ticks, all sorts of funny things might happen if you are comunicating
with someone who did not sleep.
Pavel
--
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!
next prev parent reply other threads:[~2005-01-11 0:20 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-07 18:08 Screwy clock after apm suspend Shaw
2005-01-09 22:47 ` Pavel Machek
2005-01-10 2:15 ` Alex Romosan
2005-01-10 7:28 ` Shaw
2005-01-10 7:44 ` bernard
2005-01-10 10:57 ` Pavel Machek
2005-01-10 17:48 ` Bernard Blackham
2005-01-11 0:14 ` Pavel Machek [this message]
2005-01-11 1:10 ` Nigel Cunningham
2005-01-11 3:12 ` Pavel Machek
2005-01-11 1:16 ` Bernard Blackham
2005-01-11 3:21 ` Pavel Machek
2005-01-11 12:36 ` Mikael Pettersson
2005-01-11 13:10 ` Pavel Machek
2005-01-11 14:15 ` Mikael Pettersson
2005-01-11 20:18 ` Pavel Machek
2005-01-11 3:13 ` Stephen Rothwell
2005-01-11 3:19 ` Pavel Machek
2005-01-11 12:32 ` Mikael Pettersson
-- strict thread matches above, loose matches on Subject: below --
2005-01-15 18:30 Mikael Pettersson
2005-01-16 19:47 ` Alex Romosan
2004-12-29 11:38 Mikael Pettersson
2005-01-03 17:34 ` Pavel Machek
2004-12-29 0:29 Brannon Klopfer
2004-12-29 1:18 ` Nigel Cunningham
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