ISO 7816-3 section 10.2 defines WT = WI x 960 x Fi/f seconds, store as etu, etu = Fi / (D x f) seconds, so the Fi cancels, but the D does not:
WT [etu] = WI x 960 x D
cemu dropped both (?!) -> WI x 960. The old comment explains why Fi can be dropped, which is right, but what about Di ?! sniffer gets it right (wt_wi * 960UL * wt_d), so the two state machines disagreed here again, by up to a factor of 64???!!?!!?
This was fixed in osmo-ccid-firmware in 066489d in 2020 but not ported to st2.
Additionally the waiting time was only recalculated at the end of the ATR, where D is still 1 by definition, so a PPS increasing D reprogrammed the baud rate but left the waiting time untouched??!
etu duration shrinks with D by the same factor, wall clock WT is independent of D, which is the whole point. The old code decreased the waiting time by a factor of D: after a PPS to D=8 the card emitted its NULL procedure byte at ~0.09s instead of ~0.71s with a reader deadline of ~1.43s, and the inactivity timeout fires 8x too early, which probably led to unexplained wtime_exp errors.
Update wt when WI becomes known (end of ATR) and where D changes (after the PPS response) + tests.
