Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Correct a problem with CRTSCTS flow control where output may fail to 

restart if we get multiple status interrupts before the softintr()
routine gets a chance to run.  The fix is to determine and accumulate
status line changes at the H/W interrupt level, and then check and zero
the accumulated changes when the softint() finally runs.  Many thanks
to Bill Studenmund <wrstuden@loki.stanford.edu> for finding and fixing.
This commit is contained in:
gwr 1996-10-16 20:42:14 +00:00
parent 58db3aa496
commit 3424a892b9
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sys/dev/ic/z8530tty.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: z8530tty.c,v 1.12 1996/10/13 01:37:30 christos Exp $ */
/* $NetBSD: z8530tty.c,v 1.13 1996/10/16 20:42:14 gwr Exp $ */
/*
* Copyright (c) 1994 Gordon W. Ross
@ -1066,7 +1066,15 @@ zstty_stint(cs)
zst->zst_tx_stopped = 1;
}
cs->cs_rr0_new = rr0;
/*
* We have to accumulate status line changes here.
* Otherwise, if we get multiple status interrupts
* before the softint runs, we could fail to notice
* some status line changes in the softint routine.
* Fix from Bill Studenmund, October 1996.
*/
cs->cs_rr0_delta |= (cs->cs_rr0 ^ rr0);
cs->cs_rr0 = rr0;
zst->zst_st_check = 1;
/* Ask for softint() call. */
@ -1181,9 +1189,9 @@ zstty_softint(cs)
if (zst->zst_st_check) {
zst->zst_st_check = 0;
rr0 = cs->cs_rr0_new;
delta = rr0 ^ cs->cs_rr0;
cs->cs_rr0 = rr0;
rr0 = cs->cs_rr0;
delta = cs->cs_rr0_delta;
cs->cs_rr0_delta = 0;
if (delta & ZSRR0_DCD) {
c = ((rr0 & ZSRR0_DCD) != 0);
if (line->l_modem(tp, c) == 0)