linux-kernel - Re: [PATCH][RFC v5] timekeeping: Ignore the bogus sleep time if pm

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Message-ID: <20160910094049.GA12100@sharon>
Date:   Sat, 10 Sep 2016 17:40:49 +0800
From:   Chen Yu <yu.c.chen@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>, x86@...nel.org,
        John Stultz <john.stultz@...aro.org>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        Xunlei Pang <xlpang@...hat.com>,
        "Zhang, Rui" <rui.zhang@...el.com>, linux-pm@...r.kernel.org
Subject: Re: [PATCH][RFC v5] timekeeping: Ignore the bogus sleep time if
 pm_trace is enabled

Hi,
On Fri, Sep 09, 2016 at 04:33:59PM +0200, Thomas Gleixner wrote:
> On Fri, 9 Sep 2016, Chen Yu wrote:
>
> > +extern void pm_trace_untaint_timekeeping(void);
> 
> And how exactly do you untaint it? Just by clearing the flags. That makes
> the RTC time magically correct again?
> 
> > +int arch_pm_trace_taint_pclock(void)
> > +{
> > +	return (x86_platform.get_wallclock == mach_get_cmos_time);
> > +}
> 
> Groan. I told you to do it in the mc14xxx related places. There are not
> that many in the kernel
> 
> Here is a completely uncompiled/untested patch which should address the
> issue in a halfways clean way.
> 
> Thanks,
> 
> 	tglx
> 
OK, I made some small adjustment to make it compiled without pm_trace
configured, and this version is absolutely more professional than
my previous one. I'll do some testing based on it.
Besides I have another question related to the untain
of the pm_trace_rtc_abused flag: after resume back, if the user disabled
the pm_trace, then the following suspend/resume sleep time should become
valid again IMO, because we use the delta rather than the RTC itself for
suspend/resume. So in this version it disable the injection of sleep time
once pm_trace has been used? 

Thanks,
Yu