From: Sergey Organov <sorganov@gmail.com>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Fugang Duan <fugang.duan@nxp.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Richard Cochran <richardcochran@gmail.com>
Subject: Re: [PATCH v2 net] net: fec: fix hardware time stamping by external devices
Date: Tue, 14 Jul 2020 15:39:04 +0300 [thread overview]
Message-ID: <878sfmcluf.fsf@osv.gnss.ru> (raw)
In-Reply-To: <20200712231546.4k6qyaiq2cgok3ep@skbuf> (Vladimir Oltean's message of "Mon, 13 Jul 2020 02:15:46 +0300")
Vladimir Oltean <olteanv@gmail.com> writes:
> On Mon, Jul 13, 2020 at 01:32:09AM +0300, Sergey Organov wrote:
[...]
>> > From the perspective of the mainline kernel, that can never happen.
>>
>> Yet in happened to me, and in some way because of the UAPI deficiencies
>> I've mentioned, as ethtool has entirely separate code path, that happens
>> to be correct for a long time already.
>>
>
> Yup, you are right:
>
[...]
> Very bad design choice indeed...
> Given the fact that the PHY timestamping needs massaging from MAC driver
> for plenty of other reasons, now of all things, ethtool just decided
> it's not going to consult the MAC driver about the PHC it intends to
> expose to user space, and just say "here's the PHY, deal with it". This
> is a structural bug, I would say.
>
>> > From your perspective as a developer, in your private work tree, where
>> > _you_ added the necessary wiring for PHY timestamping, I fully
>> > understand that this is exactly what happened _to_you_.
>> > I am not saying that PHY timestamping doesn't need this issue fixed. It
>> > does, and if it weren't for DSA, it would have simply been a "new
>> > feature", and it would have been ok to have everything in the same
>> > patch.
>>
>> Except that it's not a "new feature", but a bug-fix of an existing one,
>> as I see it.
>>
>
> See above. It's clear that the intention of the PHY timestamping support
> is for MAC drivers to opt-in, otherwise some mechanism would have been
> devised such that not every single one of them would need to check for
> phy_has_hwtstamp() in .ndo_do_ioctl(). That simply doesn't scale. Also,
> it seems that automatically calling phy_ts_info from
> __ethtool_get_ts_info is not coherent with that intention.
>
> I need to think more about this. Anyway, if your aim is to "reduce
> confusion" for others walking in your foot steps, I think this is much
> worthier of your time: avoiding the inconsistent situation where the MAC
> driver is obviously not ready for PHY timestamping, however not all
> parts of the kernel are in agreement with that, and tell the user
> something else.
You see, I have a problem on kernel 4.9.146. After I apply this patch,
the problem goes away, at least for FEC/PHY combo that I care about, and
chances are high that for DSA as well, according to your own expertise.
Why should I care what is or is not ready for what to get a bug-fix
patch into the kernel? Why should I guess some vague "intentions" or
spend my time elsewhere?
Also please notice that if, as you suggest, I will propose only half of
the patch that will fix DSA only, then I will create confusion for
FEC/PHY users that will have no way to figure they need another part of
the fix to get their setup to work.
Could we please finally agree that, as what I suggest is indeed a simple
bug-fix, we could safely let it into the kernel?
Thanks,
-- Sergey
next prev parent reply other threads:[~2020-07-14 12:39 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 14:26 [PATCH 0/5] net: fec: fix external PTP PHY support Sergey Organov
2020-07-06 14:26 ` [PATCH 1/5] net: fec: properly support external PTP PHY for hardware time stamping Sergey Organov
2020-07-06 15:08 ` Vladimir Oltean
2020-07-06 15:21 ` Sergey Organov
2020-07-06 15:47 ` Vladimir Oltean
2020-07-06 18:33 ` Sergey Organov
2020-07-07 7:04 ` Vladimir Oltean
2020-07-07 15:29 ` Sergey Organov
2020-07-08 11:00 ` Richard Cochran
2020-07-08 10:55 ` Richard Cochran
2020-07-06 14:26 ` [PATCH 2/5] net: fec: enable to use PPS feature without " Sergey Organov
2020-07-07 4:05 ` [EXT] " Andy Duan
2020-07-07 14:29 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 3/5] net: fec: initialize clock with 0 rather than current kernel time Sergey Organov
2020-07-06 15:27 ` Vladimir Oltean
2020-07-06 18:24 ` Sergey Organov
2020-07-07 6:36 ` Vladimir Oltean
2020-07-07 16:07 ` Sergey Organov
2020-07-07 16:43 ` Vladimir Oltean
2020-07-07 17:09 ` Sergey Organov
2020-07-07 17:12 ` Vladimir Oltean
2020-07-07 17:56 ` Sergey Organov
2020-07-08 11:15 ` Richard Cochran
2020-07-08 12:14 ` Sergey Organov
2020-07-08 11:11 ` Richard Cochran
2020-07-08 11:04 ` Richard Cochran
2020-07-08 12:24 ` Sergey Organov
2020-07-08 12:37 ` Sergey Organov
2020-07-08 14:48 ` Richard Cochran
2020-07-08 17:18 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 4/5] net: fec: get rid of redundant code in fec_ptp_set() Sergey Organov
2020-07-07 4:08 ` [EXT] " Andy Duan
2020-07-07 14:43 ` Sergey Organov
2020-07-08 5:34 ` Andy Duan
2020-07-08 8:48 ` Sergey Organov
2020-07-08 8:57 ` Andy Duan
2020-07-08 12:26 ` Sergey Organov
2020-07-06 14:26 ` [PATCH 5/5] net: fec: replace snprintf() with strlcpy() in fec_ptp_init() Sergey Organov
2020-07-11 12:08 ` [PATCH v2 net] net: fec: fix hardware time stamping by external devices Sergey Organov
2020-07-11 23:19 ` Vladimir Oltean
2020-07-12 14:16 ` Sergey Organov
2020-07-12 14:47 ` Andrew Lunn
2020-07-12 15:01 ` Vladimir Oltean
2020-07-12 17:29 ` Sergey Organov
2020-07-12 19:33 ` Vladimir Oltean
2020-07-12 22:32 ` Sergey Organov
2020-07-12 23:15 ` Vladimir Oltean
2020-07-14 12:39 ` Sergey Organov [this message]
2020-07-14 14:23 ` Vladimir Oltean
2020-07-14 14:35 ` Sergey Organov
2020-07-14 14:44 ` Vladimir Oltean
2020-07-14 16:18 ` Sergey Organov
2020-07-14 14:01 ` Richard Cochran
2020-07-14 14:27 ` Sergey Organov
2020-07-14 16:28 ` [PATCH v3 " Sergey Organov
2020-07-16 18:24 ` Jakub Kicinski
2020-07-16 20:38 ` Sergey Organov
2020-07-16 21:06 ` Jakub Kicinski
2020-07-16 21:18 ` Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 0/4] net: fec: a few improvements Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 1/4] net: fec: enable to use PPS feature without time stamping Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 2/4] net: fec: initialize clock with 0 rather than current kernel time Sergey Organov
2020-07-15 15:42 ` [PATCH net-next v2 3/4] net: fec: get rid of redundant code in fec_ptp_set() Sergey Organov
2020-07-15 15:43 ` [PATCH net-next v2 4/4] net: fec: replace snprintf() with strlcpy() in fec_ptp_init() Sergey Organov
2020-07-16 3:00 ` [EXT] [PATCH net-next v2 0/4] net: fec: a few improvements Andy Duan
2020-07-16 18:37 ` Jakub Kicinski
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