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From: Richard Cochran <richardcochran@gmail.com>
To: Heiko Thiery <heiko.thiery@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	"David S . Miller" <davem@davemloft.net>,
	Fugang Duan <fugang.duan@nxp.com>
Subject: Re: [PATCH 1/1] net: fec: ptp: avoid register access when ipg clock is disabled
Date: Tue, 23 Feb 2021 06:27:26 -0800	[thread overview]
Message-ID: <20210223142726.GA4711@hoboy.vegasvil.org> (raw)
In-Reply-To: <CAEyMn7ZM7_pPor0S=dMGbmnp0hmZMrpquGqq4VNu-ixSPp+0UQ@mail.gmail.com>

On Tue, Feb 23, 2021 at 09:00:32AM +0100, Heiko Thiery wrote:
> HI Jakub,
> 
> Am Di., 23. Feb. 2021 um 04:00 Uhr schrieb Jakub Kicinski <kuba@kernel.org>:
> > Why is the PTP interface registered when it can't be accessed?
> >
> > Perhaps the driver should unregister the PTP clock when it's brought
> > down?

I don't see any reason why a clock should stop ticking just because
the interface is down.  This is a poor driver design, but sadly it
gets copied and even defended.

> Good question, but I do not know what happens e.g. with linuxptp when
> the device that was opened before will be gone.

If a network interface goes down, ptp4l will notice via rtnl and close
the interface.  Then it re-opens the sockets on rtnl up.  However, the
file descriptor representing the dynamic posix clock stays opened.

Thanks,
Richard

  reply	other threads:[~2021-02-23 14:28 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-20  6:56 [PATCH 1/1] net: fec: ptp: avoid register access when ipg clock is disabled Heiko Thiery
2021-02-23  3:00 ` Jakub Kicinski
2021-02-23  8:00   ` Heiko Thiery
2021-02-23 14:27     ` Richard Cochran [this message]
2021-02-23 15:04       ` Heiko Thiery
2021-02-23 16:11         ` Richard Cochran
2021-02-25 13:49           ` Heiko Thiery
2021-02-25 14:05             ` Heiko Thiery
2021-02-25 17:14               ` Richard Cochran

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