Skip to contentSkip to conversation

Break on serial port

DISCUSSION cfowler 2 participants 4 messages Jun 11, 2002

lore
Share & tools
lore

cfowler

author
#0 lore raw

I remeber a while back being able to send a break on serial console. I've been unable to do this under 2.4.17. Has this feature been turned off? Is there a way to turn it back on?

Thanks,
Chris

#1 lore raw
Quoted 3 lines · cfowler

I remeber a while back being able to send a break on serial console. I've been unable to do this under 2.4.17. Has this feature been turned off? Is there a way to turn it back on?

It works fine here. Please confirm that:

1. your kernel is built with CONFIG_MAGIC_SYSRQ
2. cat /proc/sys/kernel/sysrq returns '1'
3. the serial console port is being held open by some user program (eg, getty or init)

If any of the three above are not true, then break<sysrq-key> doesn't work.

Signature · 2 lines
Russell King ([email protected])                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html
author
#2 lore raw

I can not find that ocnfig option anywher in my 2.4.17 tree. I also added CONFIG_MAGIC_SYSRQ=y to the top of .config and then did a make dep and make bzImage. Upon boot I did not see a /proc/sys/kernel/sysrq

I did notice this feature in architectures other than i386.

Chris

Quoted 25 lines · Russell King
Quoted 3 lines · cfowler

I remeber a while back being able to send a break on serial console. I've been unable to do this under 2.4.17. Has this feature been turned off? Is there a way to turn it back on?

It works fine here. Please confirm that:

1. your kernel is built with CONFIG_MAGIC_SYSRQ
2. cat /proc/sys/kernel/sysrq returns '1'
3. the serial console port is being held open by some user program (eg, getty or init)

If any of the three above are not true, then break<sysrq-key> doesn't work.

Signature · 8 lines
Russell King ([email protected])                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
#3 lore raw
In reply to cfowler
Quoted 3 lines · cfowler

I can not find that ocnfig option anywher in my 2.4.17 tree. I also added CONFIG_MAGIC_SYSRQ=y to the top of .config and then did a make dep and make bzImage. Upon boot I did not see a /proc/sys/kernel/sysrq

Oops, sorry, you need to enable CONFIG_DEBUG_KERNEL as well.

Signature · 2 lines
Russell King ([email protected])                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html