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'console=' kernel parameter questions

DISCUSSION Paul Powell 4 participants 4 messages Jan 8, 2001 – Jan 9, 2001

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Paul Powell

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#0 lore raw

Hello,

I am running an unmodified RedHat 6.2 kernel (kernel version 2.2.14-5.0)

I am trying to redirect the linux startup messages to the serial port. I've added the 'console=' parameter to my lilo.conf file. I've tried several iterations such as 'console=ttys0','console=cua0','console=ttys0,9600n8', etc....

They all fail to produce any output to the serial port although they do remove the text from my screen. When I have booted RedHat I can type 'echo blah > /dev/cua0' and I see text output from the serial port.
Interestingly when I try to echo to /dev/ttys0 I get
an IO error message. I'm using a null modem cable connect to a windows machine to watch the serial port.

My question: why can I see output when booted into RedHat but not when booting the OS? I've read that you have to compile this feature into the kernel. Does anyone know if RedHat's kernel come with this feature built in?

Your help appreciated,
Paul

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#2 lore raw
In reply to Paul Powell

I do believe RedHat kernels have this feature compiled in.

This is probably an typo in the email but it's /dev/ttyS0 . Note the capital 'S'.

Quoted 26 lines · Paul Powell

Hello,

I am running an unmodified RedHat 6.2 kernel (kernel version 2.2.14-5.0)

I am trying to redirect the linux startup messages to the serial port. I've added the 'console=' parameter to my lilo.conf file. I've tried several iterations such as 'console=ttys0','console=cua0','console=ttys0,9600n8', etc....

They all fail to produce any output to the serial port although they do remove the text from my screen. When I have booted RedHat I can type 'echo blah > /dev/cua0' and I see text output from the serial port.
Interestingly when I try to echo to /dev/ttys0 I get
an IO error message. I'm using a null modem cable connect to a windows machine to watch the serial port.

My question: why can I see output when booted into RedHat but not when booting the OS? I've read that you have to compile this feature into the kernel. Does anyone know if RedHat's kernel come with this feature built in?

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#3 lore raw
In reply to Paul Powell

append="console=/dev/ttyS0"

that should do the trick

enjoy
-kelsery

Quoted 39 lines · Paul Powell

Hello,

I am running an unmodified RedHat 6.2 kernel (kernel version 2.2.14-5.0)

I am trying to redirect the linux startup messages to the serial port. I've added the 'console=' parameter to my lilo.conf file. I've tried several iterations such as 'console=ttys0','console=cua0','console=ttys0,9600n8', etc....

They all fail to produce any output to the serial port although they do remove the text from my screen. When I have booted RedHat I can type 'echo blah > /dev/cua0' and I see text output from the serial port.
Interestingly when I try to echo to /dev/ttys0 I get
an IO error message. I'm using a null modem cable connect to a windows machine to watch the serial port.

My question: why can I see output when booted into RedHat but not when booting the OS? I've read that you have to compile this feature into the kernel. Does anyone know if RedHat's kernel come with this feature built in?

Your help appreciated,
Paul

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