Subject: Re: sys/dev/ic/z8530tty.c 1.52 -> 1.53 is broken.
To: Charles M. Hannum <>
From: Dr. Bill Studenmund <>
List: tech-kern
Date: 01/25/1999 11:51:55
On Mon, 25 Jan 1999, Charles M. Hannum wrote:

> No, in fact your change did not revert all of zsparam(); it did not
> revert the `#if 0' back to its original state.

Point taken, I mis-spoke. But this change needs to stay in. If we don't
have that part in there, then mac68k looses BADLY if someone hooks up
peripherals which supply clocks to the mac. These clocks come in on the
same pins as DCD and CTS. If we leave the #if 0, then we never will be
able to support even having these things plugged in. :-) mac68k really
does have to have a way to say don't enable interrupts on these pins. It
does it now by having these status pins not show up in cs_rr0_cts &

I'm open to other ways of doing this, but we need to be able to do it, and
this way seemed clean - if we aren't going to do anything with that status
bit in zstty_stint, then don't enable interrupts. It does make cs->cs_rr0
not cache all the bit states (if there's no interrupt enabled, we don't
follow changes), but since these clocks are around 1 MHz, that's not a

> Furthermore, I *specifically* stated why just reading rr0 at that
> point is incorrect.

True. But it's lunch time and I'm hungry. :-)

If you want to beat me to adding all the functionality you described in
your message, please do. The only thing mac68k needs to keep of the
changes to zsparam is the #if 1 part.

I'm off to lunch. :-)

Take care,