Re: [RFC PATCH net-next] net: ethtool: add support for forward error correction modes

On Thu, Nov 3, 2016 at 6:24 AM, Gal Pressman [off-list ref] wrote:

On 25/10/2016 05:50, Vidya Sagar Ravipati wrote:

quoted

SET FEC option:
root@tor: ethtool --set-fec  swp1 encoding [off | RS | BaseR | auto] autoneg [off | on]

Encoding: Types of encoding
Off    :  Turning off any encoding
RS     :  enforcing RS-FEC encoding on supported speeds
BaseR  :  enforcing Base R encoding on supported speeds
Auto   :  Default FEC settings  for  divers , and would represent

divers? :)

Drivers :)

quoted

          asking the hardware to essentially go into a best effort mode.

Here are a few examples of what we would expect if encoding=auto:
- if autoneg is on, we are  expecting FEC to be negotiated as on or off
  as long as protocol supports it
- if the hardware is capable of detecting the FEC encoding on it's
      receiver it will reconfigure its encoder to match
- in absence of the above, the configuration would be set to IEEE
  defaults.

Not sure I follow, why do we need an autoneg option if encoding type can be set to auto?

Auto is one of the FEC configuration modes  which indicates  the
drivers to set the IEEE defaults based on speed/duplex combination of
the port. i.e. RS FEC mode will be set in case of 100G/full

Auto negotiation is the configuration for the link  to negotiate the
FEC capabilities and different FEC modes with other endpoint  using
encoded bits D44:47 in base link code word.