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From: Richard Cochran <richardcochran@gmail.com>
To: "fugang.duan@freescale.com" <fugang.duan@freescale.com>
Cc: "shawn.guo@linaro.org" <shawn.guo@linaro.org>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v2 1/1] net: fec: ptp: avoid register access when ipg clock is disabled
Date: Thu, 14 Aug 2014 10:42:51 +0200	[thread overview]
Message-ID: <20140814084251.GC7555@netboy> (raw)
In-Reply-To: <e84f5b51501e4add8cf08819c64ef554@BLUPR03MB373.namprd03.prod.outlook.com>

On Thu, Aug 14, 2014 at 08:24:39AM +0000, fugang.duan@freescale.com wrote:
> 1. HW ptp is one feature of FEC IP, when the ethx interface is closed, ptp slave cannot sync with master,
>    So the ptp timer is not accurate, of couse there have discontinuities in ptp clock.

No, it just becomes a free running clock.

This is no different than the Linux system clock. It keeps running,
even if ntpd is not.

> 2. When the ethx net interface is closed, FEC IP clocks are disabled, access ptp counter register causes
>    Hw hang.

Well, then, you need to return an error, don't you?

> 3. PTP is not separate HW IP, which is one hw feature of FEC IP, when the net interface is closed, user
>    Call clock_gettime() is not reasonable.

Yes, it is. See #1.

Thanks,
Richard

  reply	other threads:[~2014-08-14  8:43 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-13  4:55 [PATCH v2 0/1] net: fec: ptp: avoid register access when ipg clock is disabled Fugang Duan
2014-08-13  4:55 ` [PATCH v2 1/1] " Fugang Duan
2014-08-13 21:19   ` Richard Cochran
2014-08-14  1:28     ` fugang.duan
2014-08-14  8:10       ` Richard Cochran
2014-08-14  8:24         ` fugang.duan
2014-08-14  8:42           ` Richard Cochran [this message]
2014-08-14  9:02             ` fugang.duan
2014-08-14  9:12               ` Richard Cochran
2014-08-14  9:26                 ` fugang.duan
2014-08-14 14:33                   ` Richard Cochran
2014-08-15  3:23                     ` fugang.duan
  -- strict thread matches above, loose matches on Subject: below --
2021-02-25 20:55 Heiko Thiery
2021-02-25 22:34 ` kernel test robot
2021-02-25 21:15 Heiko Thiery
2021-02-26  7:22 ` Heiko Thiery
2021-02-26 15:23 ` Richard Cochran
2021-02-26 23:44   ` Jakub Kicinski

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