From: Richard Cochran <richardcochran@gmail.com>
To: "Keller, Jacob E" <jacob.e.keller@intel.com>
Cc: Vladimir Oltean <olteanv@gmail.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"jakub.kicinski@netronome.com" <jakub.kicinski@netronome.com>,
"f.fainelli@gmail.com" <f.fainelli@gmail.com>,
"vivien.didelot@gmail.com" <vivien.didelot@gmail.com>,
"andrew@lunn.ch" <andrew@lunn.ch>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH net] net: dsa: sja1105: Fix double delivery of TX timestamps to socket error queue
Date: Tue, 24 Dec 2019 11:05:31 -0800 [thread overview]
Message-ID: <20191224190531.GA426@localhost> (raw)
In-Reply-To: <02874ECE860811409154E81DA85FBB58B26DF1C9@fmsmsx101.amr.corp.intel.com>
On Tue, Dec 17, 2019 at 10:21:29PM +0000, Keller, Jacob E wrote:
> > -----Original Message-----
> > From: netdev-owner@vger.kernel.org <netdev-owner@vger.kernel.org> On
> > Behalf Of Vladimir Oltean
> My understanding was that setting it prevented the stack from
> generating a SW timestamp if the hardware timestamp was going to be
> provided. Basically, this is because we would otherwise report the
> timestamp twice to applications that expect only one timestamp.
Correct.
> There were some patches from Miroslav that enabled optionally
> allowed the reporting of both SW and HW timestamps at the same time.
Not quite. If the user sets SOF_TIMESTAMPING_OPT_TX_SWHW, then there
will be two packets delivered to the error queue, one SW and one HW.
> > There are many more drivers that are in principle broken with DSA PTP,
> > since they don't even have the equivalent check for priv->hwts_tx_en.
Please stop saying that. It is not true.
> Right. I'm wondering what the correct fix would be so that we can
> fix the drivers and hopefully avoid introducing a similar issue in
> the future.
No fix is needed. MAC drivers must set SKBTX_IN_PROGRESS and call
skb_tstamp_tx() to deliver the transmit time stamp. DSA drivers
should call skb_complete_tx_timestamp() to deliver the transmit time
stamp, and they should *not* set SKBTX_IN_PROGRESS.
Thanks,
Richard
next prev parent reply other threads:[~2019-12-24 19:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-16 22:33 [PATCH net] net: dsa: sja1105: Fix double delivery of TX timestamps to socket error queue Vladimir Oltean
2019-12-17 19:57 ` Keller, Jacob E
2019-12-17 20:07 ` Vladimir Oltean
2019-12-17 22:21 ` Keller, Jacob E
2019-12-24 19:05 ` Richard Cochran [this message]
2019-12-26 18:24 ` Vladimir Oltean
2019-12-27 1:52 ` Richard Cochran
2019-12-27 15:19 ` Richard Cochran
2019-12-27 15:30 ` Vladimir Oltean
2019-12-27 17:39 ` Richard Cochran
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