From: Jason Gunthorpe <jgg@ziepe.ca>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Miroslav Lichvar <mlichvar@redhat.com>,
John Stultz <john.stultz@linaro.org>,
Prarit Bhargava <prarit@redhat.com>,
Alessandro Zummo <a.zummo@towertech.it>,
linux-rtc@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>
Subject: Re: [patch 8/8] ntp: Consolidate the RTC update implementation
Date: Mon, 7 Dec 2020 17:05:05 -0400 [thread overview]
Message-ID: <20201207210505.GM5487@ziepe.ca> (raw)
In-Reply-To: <20201206220542.355743355@linutronix.de>
On Sun, Dec 06, 2020 at 10:46:21PM +0100, Thomas Gleixner wrote:
> /*
> * If we have an externally synchronized Linux clock, then update RTC clock
> * accordingly every ~11 minutes. Generally RTCs can only store second
> @@ -686,6 +621,10 @@ static bool sync_cmos_clock(void)
> */
> static void sync_hw_clock(struct work_struct *work)
> {
> + static unsigned long offset_nsec = NSEC_PER_SEC / 2;
A comment here explaining this is the default: because the platform is
assumed to use CMOS, and by the way, this whole thing is obsolete
don't use it, seems appropriate..
The time split is clearer if you think of it from a bus/datasheet
perspective, less clear if you try to measure the system directly, eg
from an alarm. But, I think this has a better chance of some rtclib
driver authors to fill in the datasheet value at least.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2020-12-07 21:06 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-06 21:46 [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-06 21:46 ` [patch 1/8] rtc: mc146818: Prevent reading garbage Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-01-25 18:40 ` [patch 1/8] rtc: mc146818: Prevent reading garbage - bug Mickaël Salaün
2021-01-26 13:26 ` Thomas Gleixner
2021-01-26 14:17 ` Mickaël Salaün
2021-01-26 15:35 ` Thomas Gleixner
2021-01-26 17:02 ` [PATCH V2] rtc: mc146818: Detect and handle broken RTCs Thomas Gleixner
2021-01-26 18:00 ` Alexandre Belloni
2021-01-27 8:41 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2021-01-31 10:59 ` [PATCH V2] " Dirk Gouders
2021-02-01 13:53 ` Serge Belyshev
2021-02-01 19:09 ` [PATCH] rtc: mc146818: Dont test for bit 0-5 in Register D Thomas Gleixner
2021-02-01 19:24 ` [PATCH V2] " Thomas Gleixner
2021-02-01 19:32 ` Linus Torvalds
2021-02-01 19:40 ` Thomas Gleixner
2021-02-11 23:09 ` Maciej W. Rozycki
2021-02-01 19:38 ` Alexandre Belloni
2021-02-01 20:09 ` Borislav Petkov
2021-02-01 20:15 ` Dirk Gouders
2021-02-02 4:22 ` Len Brown
2021-02-02 19:40 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2021-02-03 13:00 ` [PATCH V2] " Mickaël Salaün
2020-12-06 21:46 ` [patch 2/8] rtc: mc146818: Reduce spinlock section in mc146818_set_time() Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 3/8] rtc: cmos: Make rtc_cmos sync offset correct Thomas Gleixner
2020-12-07 20:50 ` Jason Gunthorpe
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 4/8] rtc: core: Make the sync offset default more realistic Thomas Gleixner
2020-12-07 20:55 ` Jason Gunthorpe
2020-12-10 23:59 ` Alexandre Belloni
2020-12-11 0:23 ` Thomas Gleixner
2020-12-11 0:28 ` Alexandre Belloni
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 5/8] ntp: Make the RTC synchronization more reliable Thomas Gleixner
2020-12-07 12:47 ` Miroslav Lichvar
2020-12-07 20:59 ` Jason Gunthorpe
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-29 19:41 ` [patch 5/8] " Geert Uytterhoeven
2021-01-11 10:12 ` Thomas Gleixner
2021-01-11 10:40 ` Geert Uytterhoeven
2020-12-06 21:46 ` [patch 6/8] ntp, rtc: Move rtc_set_ntp_time() to ntp code Thomas Gleixner
2020-12-07 20:59 ` Jason Gunthorpe
2020-12-09 3:51 ` Alexandre Belloni
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 7/8] ntp: Make the RTC sync offset less obscure Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 8/8] ntp: Consolidate the RTC update implementation Thomas Gleixner
2020-12-07 21:05 ` Jason Gunthorpe [this message]
2020-12-11 9:23 ` Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-09 0:33 ` [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-09 4:01 ` Alexandre Belloni
2020-12-09 12:39 ` Thomas Gleixner
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