Re: [PATCH 1/1] net: fec: ptp: avoid register access when ipg clock is disabled

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 [off-list ref]:

quoted

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