linux-kernel - Re: TSC not updating after resume: Bug or Feature?

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Message-ID: <20081223220343.GA27098@plexity.net>
Date:	Tue, 23 Dec 2008 22:03:43 +0000
From:	Deepak Saxena <dsaxena@...xity.net>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Ingo Molnar <mingo@...e.hu>, Steven Rostedt <srostedt@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: TSC not updating after resume: Bug or Feature?

On Sun, Dec 21, 2008 at 10:19:12PM +0100, Thomas Gleixner wrote:
> > of cycles (~2000 ftrace entries). From following the ftrace, what is 
> > happening is that the clocksource is not updated until we run the cpu_idle() 
> > thread due to an explicit scheduling operation in the resume path that occurs 
> > via call to msleep from pci_set_power_state().  As I'm still fully groking the 
> > timekeeping code, the question(s) I have is whether this is expected behaviour 
> > and I should not assume valid timestamp data in the initial bits of the suspend path, 
> > whether this is an OLPC-specific bug, or whether I've uncovered a generic bug in 
> > the timekeeping implementation.  This is on 2.6.27.7 as I've not gotten 28-rc 
> > up and running on the XO but can move that up in priority if this behaviour
> > is different in newer kernels.
> 
> Can you please upload the full trace somewhere ? 
> 
> Thanks,

Thomas,

Sorry for the delayed response...travelling and have very limited
connectivity. I will read the thread in detail when back online in a
few days.

http://dev.laptop.org/~dsaxena/suspend-trace-1267

~Deepak

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