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From: john stultz <johnstul@us.ibm.com>
To: "Kuwahara,T." <6vvetjsrt26xsrzlh1z0zn4d2grdah@gmail.com>
Cc: Richard Cochran <richardcochran@gmail.com>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	netdev@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Arnd Bergmann <arnd@arndb.de>, Christoph Lameter <cl@linux.com>,
	David Miller <davem@davemloft.net>,
	Krzysztof Halasa <khc@pm.waw.pl>,
	Peter Zijlstra <peterz@infradead.org>,
	Rodolfo Giometti <giometti@linux.it>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH V7 1/8] ntp: add ADJ_SETOFFSET mode bit
Date: Tue, 21 Dec 2010 11:37:04 -0800	[thread overview]
Message-ID: <1292960224.2618.4.camel@work-vm> (raw)
In-Reply-To: <AANLkTi=yGoFwYt4p_LeHtAQyYgmURspO-p57UdL0sUEZ@mail.gmail.com>

On Sat, 2010-12-18 at 05:16 +0900, Kuwahara,T. wrote:
> On 12/17/10, Richard Cochran <richardcochran@gmail.com> wrote:
> > This patch adds a new mode bit into the timex structure. When set, the bit
> > instructs the kernel to add the given time value to the current time.
> >
> 
> The proposed new control mode, ADJ_SETOFFSET, is logically the same as
> ADJ_OFFSET with timex.constant == -INFINITY. 

I'm not sure if this is correct. Its more like settimeofday, only giving
a relative offset to jump the clock, rather then an absolute time. It
does not slew the clock over time like ADJ_OFFSET does.

>  So it is possible to do
> the same thing without risking forward compatibility.  (I mean by "risking
> forward compatibility" that the mode bit 0x0040 may be defined differently
> by the upstream maintainer anytime in the future.)

adjtimex is a linux specific interface, which is compatible but not
identical to the ntp specified interfaces. The ntp client code already
has Linux specific modifications, so I don't think we have to worry
about 0x40 specifically being reserved by the NTP client.

thanks
-john

  parent reply	other threads:[~2010-12-21 19:37 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-16 15:41 [PATCH V7 0/8] ptp: IEEE 1588 hardware clock support Richard Cochran
     [not found] ` <cover.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-12-16 15:41   ` [PATCH V7 1/8] ntp: add ADJ_SETOFFSET mode bit Richard Cochran
     [not found]     ` <880d82bb8120f73973db27e0c48e949014b1a106.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-12-16 17:48       ` Thomas Gleixner
2010-12-17 20:16       ` Kuwahara,T.
     [not found]         ` <AANLkTi=yGoFwYt4p_LeHtAQyYgmURspO-p57UdL0sUEZ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-21  7:56           ` Richard Cochran
     [not found]             ` <20101221075612.GA13626-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-12-21 20:57               ` Kuwahara,T.
     [not found]                 ` <AANLkTimJd5pScKTiDxuYd-h+NevYbCusyvUAqmUDXe8h-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-21 22:25                   ` john stultz
2010-12-22  7:13                     ` Richard Cochran
2010-12-22 20:27                     ` Kuwahara,T.
     [not found]                       ` <AANLkTimmTzH8+fSYmbajqZ+hU5Ps-UZaTp_1TYzjHB6P-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-23  0:00                         ` john stultz
2010-12-23  6:13                         ` Richard Cochran
2010-12-25 20:38                           ` Kuwahara,T.
2010-12-26 14:14                             ` Richard Cochran
2010-12-21 19:37         ` john stultz [this message]
2010-12-21 21:13           ` Kuwahara,T.
     [not found]             ` <AANLkTikHV-qN73Zvvvxn76vtFFKG_VNTQhF3qpqTnOrE-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-21 21:59               ` john stultz
2010-12-22  7:11                 ` Richard Cochran
2010-12-22  9:58                 ` Alexander Gordeev
2010-12-16 15:42   ` [PATCH V7 2/8] posix clocks: introduce a syscall for clock tuning Richard Cochran
     [not found]     ` <a93ce18c2987f7e102bc2ff5b12130211c222ea7.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-12-16 15:51       ` Arnd Bergmann
2010-12-16 17:55       ` Thomas Gleixner
2010-12-16 15:43   ` [PATCH V7 4/8] posix clocks: hook dynamic clocks into system calls Richard Cochran
     [not found]     ` <6241238a1df55033e50b151ec9d35ba957e43d53.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-12-16 23:20       ` Thomas Gleixner
2010-12-17  7:04         ` Richard Cochran
     [not found]           ` <20101217070450.GB2982-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-12-17 10:03             ` Thomas Gleixner
2010-12-21  8:00               ` Richard Cochran
2010-12-22  8:21               ` Richard Cochran
2010-12-16 15:44   ` [PATCH V7 5/8] ptp: Added a brand new class driver for ptp clocks Richard Cochran
2010-12-16 15:57     ` Arnd Bergmann
2010-12-16 16:08     ` Rodolfo Giometti
2010-12-16 15:44   ` [PATCH V7 7/8] ptp: Added a clock driver for the IXP46x Richard Cochran
     [not found]     ` <d2e0a5ac5eb51e9e4c7fcc94723b67c72c2f57c1.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2011-01-02  8:45       ` Pavel Machek
     [not found]         ` <20110102084505.GA3980-+ZI9xUNit7I@public.gmane.org>
2011-01-02  9:12           ` Richard Cochran
     [not found]             ` <20110102091233.GA2847-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2011-01-02  9:20               ` Pavel Machek
2011-01-03 17:07                 ` Richard Cochran
     [not found]                   ` <20110103170732.GA3700-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2011-01-06 20:04                     ` Pavel Machek
2011-01-02  9:19           ` Richard Cochran
2010-12-16 15:43 ` [PATCH V7 3/8] posix clocks: introduce dynamic clocks Richard Cochran
     [not found]   ` <8debe4d48d9a6484b7fbd35d8888524155fed977.1292512461.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-12-16 16:16     ` Arnd Bergmann
2010-12-16 20:56   ` Thomas Gleixner
2010-12-17  6:29     ` Richard Cochran
2010-12-16 15:44 ` [PATCH V7 6/8] ptp: Added a clock that uses the eTSEC found on the MPC85xx Richard Cochran
2010-12-16 15:45 ` [PATCH V7 8/8] ptp: Added a clock driver for the National Semiconductor PHYTER Richard Cochran

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