>I think what you want is to just take a timestamp in the interrupt
>routine at character reception time, and then have the line discipline
>use that timestamp rather than taking its own in the soft interrupt
>handler.

Uh, but *which* char should it be timestamping? (All of them?)

Ken Hornstein says the gadget box doesnt give a PPS signal from CHU.

The low-level interrupt handler certainly doesnt know which char to
timestamp on.  Hence Ken's sugestion, to upcall into the (CHU) ldisc
directly from the lowlevel interrupt handler.

qYour point about disabling FIFOs is spot-on.  Ken is using an
old i386 which probably has FIFOless uarts.


>Since the DCD thing adds most of the
>logic you need already, however, I seems like it would be a fine thing
>to use it for this too.

I thought so too, but without PPS, I dont see how it helps, and if Ken
did have PPS, hed just use DCD timestamps directly.