Subject: Re: Dial-in and Dial-out tty's
To: Ken Hornstein <>
From: Bill Studenmund <>
List: tech-kern
Date: 04/10/1996 13:01:52
> >As I said before, I'm willing (planning) to add these changes to the
> >new zs driver for the mac68k port this week, but would appreciate
> >suggestions on the method. Also, I'd like to dove-tail my efforts with
> >the other ports. :-)
> I think it might be a good idea to write a generic call-in, call-out layer
> (maybe merge it into the tty system?) so that every serial port device
> could have this feature with little or no modifications.  Admittedly, it
> would be a lot harder than just modifying the zs driver, but it would be
> a lot cooler :-)

I thought about something like that, but the problem is (as I see it)
that we have to play games with the code in each device's open
routine which waits for the carrier. Basically, the dial-in has
to keep on waiting if the dial-out has opened the port (even though
carrier might actually be present). So we can't not touch the tty

Though it would be nice to push parts of the dialin-dialout suport
into the tty layer (like add a variable to hold the semaphores
to coordinate the two sides).

Take care,