Re: [RFC PATCH] ethtool: add FEC bins histogramm report

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 29/07/2025 18:31, Andrew Lunn wrote:
>> The only one bin will have negative value is the one to signal the end
>> of the list of the bins, which is not actually put into netlink message.
>> It actually better to change spec to have unsigned values, I believe.
> 
> Can any of these NICs send runt packets? Can any send packets without
> an ethernet header and FCS?
> 
> Seems to me, the bin (0,0) is meaningless, so can could be considered
> the end marker. You then have unsigned everywhere, keeping it KISS.

I had to revisit the 802.3df-2024, and it looks like you are right:
"FEC_codeword_error_bin_i, where i=1 to 15, are optional 32-bit
counters. While align_status is true, for each codeword received with
exactly i correctable 10-bit symbols"

That means bin (0,0) doesn't exist according to standard, so we can use
it as a marker even though some vendors provide this bin as part of
histogram.

Thanks for the feedback!