From: Grygorii Strashko <grygorii.strashko@ti.com>
To: Kurt Kanzenbach <kurt@linutronix.de>, Michael Walle <michael@walle.cc>
Cc: Andrew Lunn <andrew@lunn.ch>, <richardcochran@gmail.com>,
<davem@davemloft.net>, <kuba@kernel.org>,
<linux-kernel@vger.kernel.org>, <linux@armlinux.org.uk>,
<mlichvar@redhat.com>, <netdev@vger.kernel.org>,
<qiangqing.zhang@nxp.com>, <vladimir.oltean@nxp.com>
Subject: Re: [PATCH RFC V1 net-next 3/4] net: Let the active time stamping layer be selectable.
Date: Tue, 5 Apr 2022 16:15:05 +0300 [thread overview]
Message-ID: <defe77d9-1a41-7112-0ef6-a12aa2b725ab@ti.com> (raw)
In-Reply-To: <87wng3pyjl.fsf@kurt>
On 05/04/2022 14:19, Kurt Kanzenbach wrote:
> On Tue Apr 05 2022, Michael Walle wrote:
>> Am 2022-04-05 11:01, schrieb Kurt Kanzenbach:
>>> On Mon Apr 04 2022, Michael Walle wrote:
>>>> That would make sense. I guess what bothers me with the current
>>>> mechanism is that a feature addition to the PHY in the *future* (the
>>>> timestamping support) might break a board - or at least changes the
>>>> behavior by suddenly using PHY timestamping.
>>>
>>> Currently PHY timestamping is hidden behind a configuration option
>>> (NETWORK_PHY_TIMESTAMPING). By disabling this option the default
>>> behavior should stay at MAC timestamping even if additional features
>>> are added on top of the PHY drivers at later stages. Or not?
>>
>> That is correct. But a Kconfig option has several drawbacks:
>> (1) Doesn't work with boards where I might want PHY timestamping
>> on *some* ports, thus I need to enable it and then stumple
>> across the same problem.
>> (2) Doesn't work with generic distro support, which is what is
>> ARM pushing right now with their SystemReady stuff (among other
>> things also for embeddem system). Despite that, I have two boards
>> which are already ready for booting debian out of the box for
>> example. While I might convince Debian to enable that option
>> (as I see it, that option is there to disable the additional
>> overhead) it certainly won't be on a per board basis.
>> Actually for keeping the MAC timestamping as is, you'd need to
>> convince a distribution to never enable the PHY timestamping
>> kconfig option.
>>
>> So yes, I agree it will work when you have control over your
>> kconfig options, after all (1) might be more academic. But I'm
>> really concerned about (2).
>
> Yes, the limitations described above are exactly one of the reasons to
> make the timestamping layer configurable at run time as done by these
> patches.
Seems like PHY TS support belongs to HW description category, so could it be device tree material,
like generic property defining which layer should do timestamping?
--
Best regards,
Grygorii, Ukraine
next prev parent reply other threads:[~2022-04-05 21:37 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-03 23:25 [PATCH RFC V1 net-next 3/4] net: Let the active time stamping layer be selectable Richard Cochran
2022-01-03 23:53 ` Russell King (Oracle)
2022-01-04 1:42 ` Richard Cochran
2022-04-04 15:05 ` Michael Walle
2022-04-04 15:20 ` Andrew Lunn
2022-04-04 17:12 ` Michael Walle
2022-04-05 5:59 ` Richard Cochran
2022-04-05 8:48 ` Michael Walle
2022-04-05 15:46 ` Richard Cochran
2022-04-05 9:01 ` Kurt Kanzenbach
2022-04-05 9:19 ` Michael Walle
2022-04-05 11:19 ` Kurt Kanzenbach
2022-04-05 13:15 ` Grygorii Strashko [this message]
2022-04-05 13:29 ` Andrew Lunn
2022-04-05 15:48 ` Richard Cochran
2022-04-06 11:18 ` Grygorii Strashko
2022-01-20 16:48 ` Vladimir Oltean
2022-01-21 3:38 ` Andrew Lunn
2022-01-21 4:05 ` Richard Cochran
2022-01-21 14:50 ` Vladimir Oltean
2022-01-21 15:28 ` Richard Cochran
2022-01-21 16:23 ` Vladimir Oltean
2022-01-22 2:08 ` Richard Cochran
2022-01-24 9:28 ` Miroslav Lichvar
2022-01-24 15:37 ` Richard Cochran
2022-01-25 15:37 ` Vladimir Oltean
2022-01-21 11:05 ` Kurt Kanzenbach
2022-01-21 15:31 ` Richard Cochran
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