On Wed, 2013-10-16 at 11:04 +0200, Hendrik Brueckner wrote:

Indeed, two callbacks change the DTR line.  The main difference is that
tiocmget/tiocmset can be called from user space by ioctl.  That's not the case
for the dtr_cts callback.  Also, tiocmget/tiocmset provide more flags that can
be changed (ST, SR, CTS, CD, RNG, RI,  ...)

Assume we would like to unify them have a single callback to change DTR, then
we have to take care of these differences.  So the question to you now is
whether you plan for a) other modem flags to be changed and b) if changing the
DTR line (or other control flags) through an ioctl?

Depending on your results, I could work on sth that helps us both and reduces
the callbacks.

Can we not just have the users of dtr_cts just call the backend's tiocmset ?

If they need to filter or clamp bits, we could handle all that in hvc_console
by caching the user intended value and passing a cooked value down to the backend..

None of that is urgent or anything, it's just odd and would be nice to cleanup.

Cheers,
Ben.