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

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Message-ID: <20160904153739.GA5400@sharon>
Date:   Sun, 4 Sep 2016 23:37:39 +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>,
        "3.17+" <stable@...r.kernel.org>, 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 Thomas, Rafael,
On Fri, Sep 02, 2016 at 09:26:51PM +0200, Thomas Gleixner wrote:
> On Wed, 31 Aug 2016, Rafael J. Wysocki wrote:
> > On Monday, August 29, 2016 12:40:39 AM Chen Yu wrote:
> > > +
> > > +	/*
> > > +	 * Make rtc-based persistent clock unusable
> > > +	 * if pm_trace is enabled, only take effect
> > > +	 * for timekeeping_suspend/resume.
> > > +	 */
> > > +	if (pm_trace_is_enabled() &&
> > > +	    x86_platform.get_wallclock == mach_get_cmos_time) {
> > > +		ts->tv_sec = 0;
> > > +		ts->tv_nsec = 0;
> > > +	}
> > 
> > I'm not sure about this.  Looks hackish.
> 
> Indeed. Can't you just keep track that pm_trace fiddled with the cmos clock
> and then discard the value either in the core or in mach_get_cmos_time()
The previous version is more straightforward, since
it ignored the bogus rtc in core. Would you please take
a glance at it too, thanks:
https://patchwork.kernel.org/patch/9287347/

Thanks,
Yu