RE: [PATCH v2 3/7] net/ixgbe: Check that SFF-8472 soft rate select is... | dpdk-dev

quoted

From: Wang, Haiyue [mailto:haiyue.wang@intel.com]
Sent: Wednesday, 22 December 2021 17.03

-----Original Message-----
From: Morten Brørup <redacted>
Sent: Wednesday, December 22, 2021 18:44

From: Wang, Haiyue [mailto:haiyue.wang@intel.com]
Sent: Wednesday, 22 December 2021 02.24

-----Original Message-----
From: Morten Brørup <redacted>
Sent: Tuesday, December 21, 2021 16:58

From: Wang, Haiyue [mailto:haiyue.wang@intel.com]
Sent: Tuesday, 21 December 2021 02.15

-----Original Message-----
From: Stephen Douthit <redacted>
Sent: Tuesday, December 21, 2021 05:33

On 12/20/21 02:53, Wang, Haiyue wrote:
-----Original Message-----
From: Stephen Douthit <redacted>
Sent: Tuesday, December 7, 2021 06:19

Make sure an SFP is really a SFF-8472 device that supports
the
optional
soft rate select feature before just blindly poking those
I2C
registers.
Skip all I2C traffic if we know there's no SFP.

Fixes: f3430431aba ("ixgbe/base: add SFP+ dual-speed
support")
Cc: stable@dpdk.org

Signed-off-by: Stephen Douthit <redacted>
---

Normally, DPDK keeps sync with this kind of release.
Working with the Linux kernel mainline drivers is good advice.

The official Intel Linux drivers seem to be ages behind the
Kernel
mainline, and they don't fully

No, the "ixgbe" drivers is updated on "7/8/2021".

https://www.intel.com/content/www/us/en/download/14302/14687/intel-
network-adapter-driver-for-pcie-intel-10-gigabit-ethernet-network-
connections-under-linux.html
So you can imagine my surprise that they didn't work on the C3338 SoC
launched by Intel in Q1'17. The
web page says that the drivers supports kernel versions 2.6.18 to
5.12, so we expected them to work
with kernel 3.19. Perhaps they haven't been tested with the C3338
SoC. Also, the test section on the
web page only mentions 64 bit distributions, so perhaps they haven't
been tested with a 32 bit kernel.
There is no test report available, so I can only speculate.

I am sorry if I came off as badmouthing the Intel out-of-tree driver.
I was only trying to convey to
the good folks at Silicom that kernel.org is a better source of
inspiration than the Intel out-of-tree
driver, which is not as up-to-date as the kernel.org driver, and thus
not the optimal source of
inspiration for driver development. The out-of-tree drivers serve a
different purpose, where they are
extremely valuable: In normal production environments where it is not
an option to compile and deploy
a kernel from scratch.

support the C3000 NICs, so don’t waste any time there! We
recently
tried using the official Intel
Linux drivers for a C3338 based project (using Kernel 3.19 in 32
bit
mode with x2APIC disabled), and
they didn't work at all. We ended up backporting the necessary
changes from the kernel mainline
instead.
From Steve's response:
     ME: "I guess this is just in C3000 reference board SDK ?"
     Steve: "It's the board covered by Intel Doc # 574437."

I check the doc "Last Updated: 11/07/2018".... It should be some
kind
of customer release, that's why
they are not in the official *open source* Linux driver, so keep
your
patch set as private.
I didn't mention it explicitly, but I'm not involved with Silicom,
and was not referring to their
hardware. The hardware board we had problems with is currently in
volume production at a major ODM.
But I guess that it is usually being deployed with a 64 bit kernel,
as opposed to the 32 bit kernel we
were using.
I understood, but we need to follow the open source vs customer release
policy,
so not everything is upstream.

The ixgbe (especially in base directory) code is so stable, so in other
words,
this patch set can be rebased easily. ;-)

If the patch is about ixgbe ethdev part (vs kernel netdev), it will be
welcomed,
since our team mainly work on this (And the base code is mainly
developed by the
kernel team, that's why I recommend to send it to
https://lists.osuosl.org/mailman/listinfo/intel-wired-lan).

Hope this will make things clear. ;-)
ACK. :-)

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