-----Original Message-----
From: Jakub Kicinski <kuba@kernel.org>
Sent: Tuesday, August 23, 2022 3:18 PM
To: Keller, Jacob E <jacob.e.keller@intel.com>
Cc: netdev@vger.kernel.org; Greenwalt, Paul <redacted>
Subject: Re: [PATCH net-next 2/2] ice: add support for Auto FEC with FEC disabled
via ETHTOOL_SFECPARAM

On Tue, 23 Aug 2022 08:04:38 -0700 Jacob Keller wrote:

quoted

The default Link Establishment State Machine (LESM) behavior does not

LESM is the algo as specified by the IEEE standard? If so could you add
the citation (section of the spec where it's defined)?

Hm. I am not sure if its part of IEEE standard or if its just the name we used for that section of our firmware. I'll get back on this and if its not part of a standard I'll rephrase this a bit so thats clear.

Is disabling the only customization we may want?

Of that, I'm not sure.

quoted

allow the use of FEC disabled if the media does not support FEC
disabled. However users may want to override this behavior.

To support this, accept the ETHTOOL_FEC_AUTO | ETHTOOL_FEC_OFF as a

request

quoted

to automatically select an appropriate FEC mode including potentially
disabling FEC.

This is distinct from ETHTOOL_FEC_AUTO because that will not allow the LESM
to select FEC disabled. It is distinct from ETHTOOL_FEC_OFF because
FEC_OFF will always disable FEC without any LESM automatic selection.

This *does* mean that ice is now accepting one "bitwise OR" set for FEC
configuration, which is somewhat against the recommendations made in
6dbf94b264e6 ("ethtool: clarify the ethtool FEC interface"), but I am not
sure if the addition of an entirely new ETHTOOL_FEC_AUTO_DIS would make

any

quoted

sense here.

With this change, users can opt to allow automatic FEC disable via

  ethtool --set-fec ethX encoding auto off