12/05/2022 19:01, Jeff Daly:
> From: Thomas Monjalon <tho...@monjalon.net>
> > 11/05/2022 13:43, Zhang, Qi Z:
> > > From: Jeff Daly <je...@silicom-usa.com>
> > > >
> > > > 1ca05831b9b added a check that SDP3 (used as a TX_DISABLE output to
> > > > the SFP cage on these cards) is not asserted to avoid incorrectly
> > > > reporting link up when the SFP's laser is turned off.
> > > >
> > > > ff8162cb957 limited this workaround to fiber ports
> > > >
> > > > This patch:
> > > > * Adds devarg 'fiber_sdp3_no_tx_disable' not all fiber ixgbe devs use
> > > > SDP3 as TX_DISABLE
> > > >
> > > > Fixes: 1ca05831b9b ("net/ixgbe: fix link status")
> > > > Fixes: ff8162cb957 ("net/ixgbe: fix link status")
> > > > Cc: sta...@dpdk.org
> > > >
> > > > Signed-off-by: Jeff Daly <je...@silicom-usa.com>
> > >
> > > Acked-by: Qi Zhang <qi.z.zh...@intel.com>
> > >
> > > Applied to dpdk-next-net-intel.
> >
> > There is a lack of context in this description.
> > I don't know what SDP3 and TX_DISABLE refers to.
> > Please make more complete sentences, thanks.
> >
>
> I don't want to sound obtuse here, but this is a fix to a specific Intel NIC
> driver. Any symbols or abbreviations or definitions used in a device driver
> are almost always in the manual. While SDP3 means something specific to the
> Intel 82599 and X550 (and probably others), it probably doesn't appear in a
> driver from Marvell for example. So, in this case [S]oftware [D]efined
> [P]ins [3] (out of 0-3) is specifically talking about the Intel X550. I'm
> familiar enough with the hardware to recognize that, but if I was to look at
> a Marvell driver and saw something I didn't recognize like that, I'd be
> checking the Marvell manual.
Of course we can spend hours checking code and manuals.
But if we need to look to a lot of commits,
it is a lot more convenient to have a summary of this information
in the commit log.
> What I'm describing here is the fact that the TX_DISABLE signal (a signal
> defined in the SFP spec) from the NIC as implemented by the Software Defined
> Pin (3) by many (most?) implementations that are using this Intel driver, is
> not specifically the *only* use of SDP3. A later patch limited the check
> (correctly) to fiber implementations (which is the only thing that makes
> sense), and *this* patch adds a module switch for platforms to disable this
> check in the event that they (as they are perfectly allowed to) don't use
> SDP3 as TX_DISABLE.
Thank you for the explanation.
