Re: Ethtool : PRBS feature

Looks like they are different derivations of the polynomial for the
given pattern. For example PRBS11 is 1 + x^9 + x^11

802.3 section "72.6.10.2.6 Training pattern" agrees with you.

, but PRBS11_0 is 1

+ x^5 + x^6 + X^10 + x^11. That is one thing to think about. When we
say PRBS7 the assumption is we are all talking about 1 + x^6 + x^7 for
the polynomial.

I could be missing it, but i could not quickly find PRBS7 in the
standard!

We may want to have that clearly recorded somewhere so
there isn't any confusion on which polynomials we are using for this
testing as there is always a risk that somebody is playing with
bleeding edge hardware and ends up defining a PRBS polynomial
differently than what is expected.

I would probably give a reference to 802.3, at least for standard
tests. If a vendor has made up their own test sequences then yes,
there needs to be a clear definition of what it is.

I almost wonder if we couldn't
define the sequence as a bitmap instead of an enum with each bit
representing which fields are in the sequence.

Not everything is a polynomial. Look at SSPQR, 120.5.11.2.3 SSPRQ test
pattern.

	Andrew