On Feb 09, 2017, at 11:42, sdncurious [off-list ref] wrote:

I am still at a loss as to why transpose is required in case of HW
time stamping. If STF is used for both Tx and Rx time stamping the
timing is absolutely correct.

Perhaps this will help. The specific transposition is:

  transposed_timestamp_ns = timestamp_ns + (frame_len_bits * 1000000000) / (interface_speed * 1000000)

The transposition is applied to received timestamps only.

Denny