On 26/09/18 09:47, Ariel Almog wrote:
> I was won
Truncated sentence? ("... wondering"?)
> I find the ability to set off, auto and specific FEC mode in the same
> command confusing.
I didn't try to define semantics here since each driver currently does
something slightly different. Probably the configuration space that's
meaningful is different for each piece of hardware anyway.
> Here are some examples
>
> 1. What is the expected result of 'off' & other FEC mode such as 'RS'?
> -'off'?
> -'RS'?
> -automatic selection {'off','RS'}? w/o setting of auto?
In sfc, 'off' overrides everything else.
The meaning (again, in sfc) of a combination of 'auto' and a specific mode
(e.g. 'rs') is "prefer the specified mode, but fall back to autoneg if
it's not supported". The combination {'rs', 'baser'} (with or without
'auto') means "use the strongest FEC supported", i.e. it will attempt to
negotiate FEC even if the cable & link partner don't request it (e.g. a
short cable).
For us, those semantics make sense (our HW has a notion of 'supported'
and 'requested' bits for each FEC type for each of local-device, cable
and link-partner, and uses the strongest FEC mode that's supported by
everyone and requested by anyone); but if something else is a better fit
for your hardware I wouldn't worry too much about the inconsistency —
people using this functionality will hopefully have read the hardware's
user manual...
-Ed
