rde@UUNET.UU.NET (Richard Evans) (01/18/89)
This is a note about a couple of problems we had when using GNU Emacs
version 18.49 with Sun ALM-2 (16 port multiplexor) boards. It's quite
likely that you know about these fixes already, even though ALM-2s are
relatively rare.
I would be pleased if you could let me know if this information was any
use.
There were two separate problems, depending on the version of the Sun
operating system:
1. Sun operating system version 3.5
====================================
On exit from Emacs, a terminal attached to an ALM-2 line would hang for ever;
you had to reboot the machine to fix it. I cured this by including the
"s-bsd4-2.h" file, rather than "s-bsd4-3.h" in the "config.h" file, and
remaking Emacs. We got the source from a Sun Users Group tape, so I had
assumed that the "config.h" was suitable for all Suns!
2. Sun operating system version 4.0.1
=====================================
The problem again involved terminals hanging up on exit; this time they could
be unblocked by typing CTRL/S and CTRL/Q, but it was still a nuisance.
Here is a copy of some information I sent to Sun UK about the fix I made:
The fault seems to occur when switching to or from raw mode when characters
are being output. GNU Emacs uses the TIOCSETN ioctl, which does not delay
until output is quiescent. Changing this in two places to TIOCSETP seems to
fix the problem (note that these hang ups did not occur with OS 3.5, so I
still think it is caused by a bug in the drivers).
We are using GNU Emacs version 18.49; the changes described below may not
be exactly correct for other versions, and indeed may already have been made
in the States.
The file 'sysdep.c' contains the terminal handling stuff. Here is the output
from 'diff -c srcx/sysdep.c src/sysdep.c' (srcx/sysdep.c is the original,
src/sysdep.c the modified version):
*** srcx/sysdep.c Tue Oct 13 11:29:40 1987
--- src/sysdep.c Tue Jan 17 14:34:19 1989
***************
*** 734,740 ****
--- 734,744 ----
SYS$QIOW (0, input_chan, IO$_SETMODE, &input_iosb, 0, 0,
&sg.class, 12, 0, 0, 0, 0);
#else
+ #ifdef SUNOS4_0
+ ioctl (0, TIOCSETP, &sg);
+ #else
ioctl (0, TIOCSETN, &sg);
+ #endif /* Not SUNOS4_0 */
#endif /* not VMS */
#ifdef F_SETFL
***************
*** 921,927 ****
--- 925,935 ----
SYS$QIOW (0, input_chan, IO$_SETMODE, &input_iosb, 0, 0,
&old_gtty.class, 12, 0, 0, 0, 0);
#else /* not VMS */
+ #ifdef SUNOS4_0
+ while (ioctl (0, TIOCSETP, &old_gtty) < 0 && errno == EINTR);
+ #else
while (ioctl (0, TCSETAW, &old_gtty) < 0 && errno == EINTR);
+ #endif /* Not SUNOS4_0 */
#endif /* not VMS */
}
------
The two ioctls changed are in the #ifdef SUNOS4_0s. For cleanliness, I created
a new header file (s-sunos4-0.h) which should be included in 'config.h' instead
of 's-bsd4-2.h'. The new header defines the SUNOS4_0 flag and also sets up the
special options needed to link GNU Emacs under OS 4.0 (it can't use dynamic
linking because it dumps itself). As I said, it is likely that something of
this sort has already been done by OS 4.0 users in the States; they may not
have made the ioctl change, because there aren't many ALM-2s around.
Here is the complete 's-sunos4-0.h':
/* Definitions file for GNU Emacs running on SunOS 4.0.x
Copyright (C) 1985, 1986 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY. No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing. Refer to the GNU Emacs General Public
License for full details.
Everyone is granted permission to copy, modify and redistribute
GNU Emacs, but only under the conditions described in the
GNU Emacs General Public License. A copy of this license is
supposed to have been given to you along with GNU Emacs so you
can know your rights and responsibilities. It should be in a
file named COPYING. Among other things, the copyright notice
and this notice must be preserved on all copies. */
/*
* Define symbols to identify the version of Unix this is.
* Define all the symbols that apply correctly.
*/
#ifndef SUNOS4_0
#define SUNOS4_0
#endif /* SUNOS4_0 */
#include "s-bsd4-2.h"
/* Special linking options for SunOS 4.0 */
#define LD_SWITCH_SYSTEM -X -Bstatic -e __start
---------------
Richard Evans
Topexpress Ltd.
Poseidon House
Castle Park
Cambridge CB3 0RD
UK
Tel: 0223 462121
Fax: 0223 315057rms@WHEATIES.AI.MIT.EDU (Richard Stallman) (01/20/89)
Using TIOCSETP is in general a bug, because it throws away input.