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From: Thomas Gleixner <tglx@linutronix.de>
To: Leonid Bloch <lb.workbox@gmail.com>, linux-kernel@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Leonid Bloch <lb.workbox@gmail.com>
Subject: Re: [PATCH] rtc: Do not sync CMOS clock when CONFIG_RTC_SYSTOHC is not set
Date: Mon, 27 Apr 2020 11:30:41 +0200	[thread overview]
Message-ID: <875zdls2bi.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200426013521.43087-1-lb.workbox@gmail.com>

Leonid Bloch <lb.workbox@gmail.com> writes:
> According to documentation in 'drivers/rtc/Kconfig', if
> 'CONFIG_RTC_SYSTOHC' is set, then:
>
> '''
> The system time (wall clock) will be stored in the RTC specified by
> RTC_HCTOSYS_DEVICE approximately every 11 minutes if userspace reports
> synchronized NTP status.
> '''
>
> However in reality, even if 'CONFIG_RTC_SYSTOHC' is not set, the RTC
> is still sometimes synced with the system time: at least when the RTC
> driver is 'rtc_cmos', in certain situations. This commit prevents
> that.

But in reality sync_cmos_clock() depends on CONFIG_GENERIC_CMOS_UPDATE
and has nothing to do with CONFIG_RTC_SYSTOHC.

That's a historical leftover from the days where RTCs were strictly a
platform/architecture specific issue.

Your change would break all architectures which still depend on that.

Thanks,

        tglx

  reply	other threads:[~2020-04-27  9:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-26  1:35 [PATCH] rtc: Do not sync CMOS clock when CONFIG_RTC_SYSTOHC is not set Leonid Bloch
2020-04-27  9:30 ` Thomas Gleixner [this message]
2020-04-27 14:36   ` Leonid Bloch
  -- strict thread matches above, loose matches on Subject: below --
2020-04-09 20:46 Leonid Bloch

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