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Date:   Mon, 5 Jul 2021 11:44:01 -0700
From:   Richard Cochran <richardcochran@gmail.com>
To:     "Y.b. Lu" <yangbo.lu@nxp.com>
Cc:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>,
        "mptcp@lists.linux.dev" <mptcp@lists.linux.dev>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Mat Martineau <mathew.j.martineau@linux.intel.com>,
        Matthieu Baerts <matthieu.baerts@tessares.net>,
        Shuah Khan <shuah@kernel.org>,
        Michal Kubecek <mkubecek@suse.cz>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>, Rui Sousa <rui.sousa@nxp.com>,
        Sebastien Laveze <sebastien.laveze@nxp.com>
Subject: Re: [net-next, v5, 08/11] net: sock: extend SO_TIMESTAMPING for PHC
 binding
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On Mon, Jul 05, 2021 at 08:19:30AM +0000, Y.b. Lu wrote:
> When several ptp virtual clocks are created, the ptp physical clock is guaranteed for free running.
> 
> What I think is, for timestamping, if no flag SOF_TIMESTAMPING_BIND_PHC, the timestamping keeps using ptp physical clock.
> If application wants to bind one ptp virtual clock for timestamping, the flag SOF_TIMESTAMPING_BIND_PHC should be set and clock index should be provided.
> After all, several ptp virtual clocks created are likely for different timescale/use case. There should be a method for any of applications to select the right one to use.
> 
> Does it make sense?

Yes, indeed.  I totally forgot that the user space PTP stack has
network sockets bond to interfaces, and they are completely separate
from the PHC clockid_t.  Need more sleep...

Thanks,
Richard