From: Miroslav Lichvar <mlichvar@redhat.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: netdev@vger.kernel.org, David Miller <davem@davemloft.net>,
Jacob Keller <jacob.e.keller@intel.com>,
John Stultz <john.stultz@linaro.org>
Subject: Re: [PATCH RFC net-next 1/1] ptp: add an ioctl to compare PHC time with system time
Date: Fri, 28 Sep 2012 09:53:03 +0200 [thread overview]
Message-ID: <20120928075303.GB29438@localhost> (raw)
In-Reply-To: <f0c20e2d1a303b0247b1e0e0def19f131de162ff.1348768886.git.richardcochran@gmail.com>
On Thu, Sep 27, 2012 at 08:12:16PM +0200, Richard Cochran wrote:
> This patch adds an ioctl for PTP Hardware Clock (PHC) devices that allows
> user space to measure the time offset between the PHC and the system
> clock. Rather than hard coding any kind of estimation algorithm into the
> kernel, this patch takes the more flexible approach of just delivering
> an array of raw clock readings. In that way, the user space clock servo
> may be adapted to new and different hardware clocks.
Would it make sense to extend the ioctl to allow also comparing the
PHC with another PHC or perhaps even a different system clock than
CLOCK_REALTIME?
I'm thinking if someone wanted to synchronize one PHC to another, it
should be better to work with phc1-phc2 offsets than combine phc1-sys
and sys-phc2 offsets.
--
Miroslav Lichvar
next prev parent reply other threads:[~2012-09-28 7:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 18:12 [PATCH RFC net-next 0/1] ptp: add pseudo pps ioctl Richard Cochran
2012-09-27 18:12 ` [PATCH RFC net-next 1/1] ptp: add an ioctl to compare PHC time with system time Richard Cochran
2012-09-28 7:53 ` Miroslav Lichvar [this message]
2012-09-28 8:26 ` Richard Cochran
2012-09-28 8:50 ` Miroslav Lichvar
2012-10-01 22:33 ` Keller, Jacob E
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