Date: Tue, 13 Apr 2010 17:24:35 -0400 From: Mike Tancsa <mike@sentex.net> To: freebsd-questions@freebsd.org Subject: disabling all serial input / output at boot time Message-ID: <201004132124.o3DLOaij062046@lava.sentex.ca>
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I have an embedded device (Alix box) that is running RELENG_8 off a
CF that is designed to monitor / control a serial sensor device. The
sensor is quite chatty and is always outputing data at 115200. The
problem is that this will interrupt the boot process.
I managed to get around boot0 by making this small hack (if there is
a better way, please let me know.
0(ich10)# diff -u boot0.S.o boot0.S
--- boot0.S.o 2010-04-13 15:11:22.000000000 -0400
+++ boot0.S 2010-04-13 15:27:02.000000000 -0400
@@ -356,7 +356,9 @@
*/
#ifndef SIO
movb $0x1,%ah # BIOS: Check
- int $0x16 # for keypress
+ /* int $0x16 */ # for keypress
+ testb $0x02,%ah
+
#else /* SIO */
movb $0x03,%ah # BIOS: Read COM
call bioscom
@@ -538,7 +540,8 @@
pushw %bx # Save
movw $0x7,%bx # Page:attribute
movb $0xe,%ah # BIOS: Display
- int $0x10 # character
+ /* int $0x10 # character */
+ nop
popw %bx # Restore
#else /* SIO */
movb $0x01,%ah # BIOS: Send
1(ich10)#
and I added in /boot/loader.conf
console="nullconsole"
I also tried
# cat /boot.config
-nmq
But when I put an inline serial monitor to see why things are getting
hung up, I still see the "spinning slashes" (/) show up. After that,
it seems the boot process is hung and it never fully boots. There
seems to be a window of opportunity where key presses on the serial
console stop/pause one of the boot stages.. but boot.config should
prevent that no ? I even tried to "fake" it out, but trying to make
com2, the console in /boot/device.hints, but I still see the spinning
slashes on com1
Is there any way to completely disable serial interaction and to
truly make the bootup process quiet and non interactive ?
---Mike
--------------------------------------------------------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike@sentex.net
Providing Internet since 1994 www.sentex.net
Cambridge, Ontario Canada www.sentex.net/mike
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