>Number:         4565
>Category:       port-i386
>Synopsis:       Accessing /dev/tty01 after apm sleep hangs machine.
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Nov 23 02:50:01 1997
>Last-Modified:
>Originator:     R. C. Dowdeswell
>Organization:
	The Fall of Imrryr
>Release:        1.3_ALPHA
>Environment:
Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.3_ALPHA (KINSLAYER) #0: Wed Nov 12 12:21:11 PST 1997
    elric@mars:/usr/src/sys/arch/i386/compile/KINSLAYER
cpu0: family 4 model 3 step 5
cpu0: Intel 486DX2 (486-class)
real mem  = 20836352
avail mem = 17989632
using 279 buffers containing 1142784 bytes of memory
mainbus0 (root)
isa0 at mainbus0
com0 at isa0 port 0x3f8-0x3ff irq 4: ns8250 or ns16450, no fifo
lpt0 at isa0 port 0x378-0x37b irq 7
wdc0 at isa0 port 0x1f0-0x1f7 irq 14
wd0 at wdc0 drive 0: <TOSHIBA MK2124FC>
wd0: 124MB, 934 cyl, 16 head, 17 sec, 512 bytes/sec
wd0: using 1-sector 16-bit pio transfers, chs addressing
npx0 at isa0 port 0xf0-0xff: using exception 16
vt0 at isa0 port 0x60-0x6f irq 1
vt0: generic, 80 col, color, 8 scr, mf2-kbd, [R3.32]
pms0 at vt0 irq 12
vt0: console
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
pcic0 at isa0 port 0x3e0-0x3e1 iomem 0xd0000-0xd3fff: using irq 3
pcic0: controller 0 (Intel 82365SL Revision 1) has socket A only
pcmcia0 at pcic0 controller 0 socket 0
IBM, w95 Home and Away Credit Card , Version 001, Card Assy Part Number - 10H4706 (manufacturer 0xa4, product 0x2e) function 0 not configured
com1 at pcmcia0 function 1 port 0x3e8-0x3ef: ns16550a, working fifo
pcmcia0: card irq 5
apm0 at mainbus0: Power Management spec V1.0 (BIOS mgmt disabled)
apm0: A/C state: on
apm0: battery charge state:charging
biomask 4040 netmask 4040 ttymask 50ca
boot device: wd0
root on wd0a dumps on wd0b
root file system type: ffs

>Description:

Accessing /dev/tty01 after the machine has been sleeping hangs the
machine completely.  Not even the kernel debugger wants to work...
So a more complete description is a bit difficult.  Unfortunately,
I do not have the kernel source on this laptop, and it will be a
while before I can get anything like that...

>How-To-Repeat:
$ su
# zzz
[ a bit of screen flicker, and then its off ]
[ turn it back on ]
[ a bit more screen flicker... ]
# cu -9600 -l /dev/tty01
[ Machine hangs, will not even respond to ctl-alt-esc ]

Also, these lines work in the place of cu -9600...:
# </dev/tty01
# >/dev/tty01

And I'd imagine that anything that twiddles /dev/tty01.

>Fix:

Not sure, the only workaround that I have is to reboot the machine
directly before trying to use the modem if it has slept since the
last reboot.
>Audit-Trail:
>Unformatted: