From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Igor Plyatov <plyatov@gmail.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
linux-kernel@vger.kernel.org,
Alessandro Zummo <a.zummo@towertech.it>,
rtc-linux@googlegroups.com, util-linux@vger.kernel.org
Subject: Re: 500 ms delay in time saved into RTC
Date: Mon, 19 Feb 2018 11:07:54 +0100 [thread overview]
Message-ID: <20180219100754.GL14177@piout.net> (raw)
In-Reply-To: <c91e0079-c31f-715d-bb2e-648af34565d7@gmail.com>
On 19/02/2018 at 12:16:04 +0300, Igor Plyatov wrote:
> Dear Rasmus,
>
> thank you very much for explanation!
>
> I have set "RTC_SET_DELAY_SECS = 0.0" in hwclock.c and got acceptable
> result.
>
> It wonder why such critical function does not implemented on kernel level in
> RTC driver?
> It is very strange to rely on specific HW in user space SW.
>
Because of the way the API is designed, handling the MC146818A oddity is
not possible in the driver (i.e. 50% of the time, it will be too late
to handle it).
You can use busybox hwclock which has the x86 insanity commented out:
https://git.busybox.net/busybox/tree/util-linux/hwclock.c
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com
next prev parent reply other threads:[~2018-02-19 10:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-19 6:40 500 ms delay in time saved into RTC Igor Plyatov
2018-02-19 7:11 ` Rasmus Villemoes
2018-02-19 9:16 ` Igor Plyatov
2018-02-19 10:07 ` Alexandre Belloni [this message]
2018-02-19 10:37 ` Rasmus Villemoes
2018-02-19 11:03 ` Karel Zak
2018-02-19 11:31 ` Igor Plyatov
2018-07-18 12:12 ` Karel Zak
2018-02-25 0:34 ` Alexandre Belloni
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