>Number:         4321
>Category:       port-i386
>Synopsis:       pccons can leave junk in tty input queue after X exits
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 22 18:05:01 1997
>Last-Modified:
>Originator:     Chris G. Demetriou
>Organization:
Kernel Hackers 'r' Us
>Release:        NetBSD-current (1.3ALPHA) as of October 22, 1997
>Environment:
System: NetBSD brick.demetriou.com 1.2G NetBSD 1.2G (BRICK) #1: Sat Oct 18 18:08:21 PDT 1997     cgd@brick.demetriou.com:/a/users/cgd/netbsd-src/src.pcmcia/sys/arch/i386/compile/BRICK i386
(but with an updated kernel being used for testing.)

>Description:
	The i386 pccons driver can and often does leave "junk" in
	the tty input queue when brought out of X mode.

	This "junk" is actually event-mode ("X mode") keyboard data,
	which wasn't processed by the server but which was left in
	the queue when the tty was switched back to 'normal' mode.

>How-To-Repeat:
	log in on a pccons console, with csh as your shell.  xinit.
	control-alt-backspace to exit the server.  hit return.  notice
	the garbage that showed up as input to the shell.

>Fix:
	Arguably, the correct fix is to avoid using the same device
	for tty input as you do for X keyboard input.  However, the
	following patch works around the problem.

	Arguably the X server should do this, as well, but it doesn't
	hurt for the driver to do it.

Index: pccons.c
===================================================================
RCS file: /cvsroot/src/sys/arch/i386/isa/pccons.c,v
retrieving revision 1.113
diff -c -r1.113 pccons.c
*** pccons.c	1997/10/09 02:05:01	1.113
--- pccons.c	1997/10/23 00:58:41
***************
*** 49,54 ****
--- 49,55 ----
  #include <sys/user.h>
  #include <sys/select.h>
  #include <sys/tty.h>
+ #include <sys/fcntl.h>
  #include <sys/uio.h>
  #include <sys/callout.h>
  #include <sys/systm.h>
***************
*** 698,706 ****
--- 699,709 ----
  #ifdef XSERVER
  	case CONSOLE_X_MODE_ON:
  		pc_xmode_on();
+ 		ttyflush(tp, FREAD);
  		return 0;
  	case CONSOLE_X_MODE_OFF:
  		pc_xmode_off();
+ 		ttyflush(tp, FREAD);
  		return 0;
  	case CONSOLE_X_BELL:
  		/*
	
>Audit-Trail:
>Unformatted: