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From: Kurt Kanzenbach <kurt@linutronix.de>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Richard Cochran <richardcochran@gmail.com>,
	Kamil Alkhouri <kamil.alkhouri@hs-offenburg.de>,
	ilias.apalodimas@linaro.org
Subject: Re: [PATCH net-next v6 4/7] net: dsa: hellcreek: Add support for hardware timestamping
Date: Tue, 06 Oct 2020 15:30:36 +0200	[thread overview]
Message-ID: <87tuv77a83.fsf@kurt> (raw)
In-Reply-To: <20201006072847.pjygwwtgq72ghsiq@skbuf>

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On Tue Oct 06 2020, Vladimir Oltean wrote:
> On Tue, Oct 06, 2020 at 08:27:42AM +0200, Kurt Kanzenbach wrote:
>> On Sun Oct 04 2020, Vladimir Oltean wrote:
>> > On Sun, Oct 04, 2020 at 01:29:08PM +0200, Kurt Kanzenbach wrote:
>> >> +/* Enabling/disabling TX and RX HW timestamping for different PTP messages is
>> >> + * not available in the switch. Thus, this function only serves as a check if
>> >> + * the user requested what is actually available or not
>> >> + */
>> >
>> > Correct me if I'm wrong, but to the user it makes zero difference
>> > whether the hardware takes timestamps or not.
>> 
>> Why not? I think it makes a difference to the user b/o the precision.
>> 
>> > What matters is whether the skb will be delivered to the stack with a
>> > hardware timestamp or not, so you should definitely accept a
>> > hwtstamp_config with TX and RX timestamping disabled.
>> >
>> 
>> Sorry, I cannot follow you here.
>
> What I meant to say is that there is no reason you should refuse the
> disabling of hardware timestamping. Even if that operation does not
> really prevent the hardware from taking the timestamps, you simply
> ignore the timestamps in the driver.

That's the point. The user (or anybody else) cannot disable hardware
stamping, because it is always performed. So, why should it be allowed
to disable it even when it cannot be disabled?

Thanks,
Kurt

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  reply	other threads:[~2020-10-06 13:30 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-04 11:29 [PATCH net-next v6 0/7] Hirschmann Hellcreek DSA driver Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 1/7] net: dsa: Add tag handling for Hirschmann Hellcreek switches Kurt Kanzenbach
2020-10-04 11:56   ` Vladimir Oltean
2020-10-05  6:14     ` Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 2/7] net: dsa: Add DSA driver " Kurt Kanzenbach
2020-10-04 12:56   ` Vladimir Oltean
2020-10-06  6:09     ` Kurt Kanzenbach
2020-10-06  9:20       ` Vladimir Oltean
2020-10-06 10:13         ` Kurt Kanzenbach
2020-10-06 11:32           ` Vladimir Oltean
2020-10-06 12:37             ` Vladimir Oltean
2020-10-06 13:23             ` Kurt Kanzenbach
2020-10-06 13:42               ` Vladimir Oltean
2020-10-06 14:05                 ` Kurt Kanzenbach
2020-10-06 14:10                   ` Vladimir Oltean
2020-10-06 13:56               ` Vladimir Oltean
2020-10-06 14:13                 ` Kurt Kanzenbach
2020-10-11 12:29                 ` Kurt Kanzenbach
2020-10-11 15:30                   ` Vladimir Oltean
2020-10-12  5:37                     ` Kurt Kanzenbach
2020-10-16 12:11                       ` Kurt Kanzenbach
2020-10-16 15:43                         ` Vladimir Oltean
2020-10-16 16:56                           ` Florian Fainelli
2020-10-17 10:06                             ` Kurt Kanzenbach
2020-10-17 15:57                             ` Vladimir Oltean
2020-10-08 11:49           ` Vladimir Oltean
2020-10-09  5:58             ` Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 3/7] net: dsa: hellcreek: Add PTP clock support Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 4/7] net: dsa: hellcreek: Add support for hardware timestamping Kurt Kanzenbach
2020-10-04 14:30   ` Vladimir Oltean
2020-10-06  6:27     ` Kurt Kanzenbach
2020-10-06  7:28       ` Vladimir Oltean
2020-10-06 13:30         ` Kurt Kanzenbach [this message]
2020-10-06 13:32           ` Vladimir Oltean
2020-10-06 13:56             ` Kurt Kanzenbach
2020-10-06 14:01               ` Vladimir Oltean
2020-10-07 10:39                 ` Kurt Kanzenbach
2020-10-07 10:54                   ` Vladimir Oltean
2020-10-08  8:34                     ` Kurt Kanzenbach
2020-10-08  9:44                       ` Vladimir Oltean
2020-10-08 10:01                         ` Kurt Kanzenbach
2020-10-08 12:55                           ` Kamil Alkhouri
2020-10-08 15:09                             ` Vladimir Oltean
2020-10-12 12:53                               ` Kamil Alkhouri
2020-10-12 21:42                                 ` Richard Cochran
2020-10-14  9:57                                   ` Vladimir Oltean
2020-10-14 11:01                                     ` Richard Cochran
2020-10-14 11:37                                       ` Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 5/7] net: dsa: hellcreek: Add PTP status LEDs Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 6/7] dt-bindings: Add vendor prefix for Hirschmann Kurt Kanzenbach
2020-10-04 11:29 ` [PATCH net-next v6 7/7] dt-bindings: net: dsa: Add documentation for Hellcreek switches Kurt Kanzenbach

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