How to see kernel pr_err error messages.

[r...@dwf.com]

Im looking at some kernel code, and there are 'pr_err' error messages in
it that would help me discover my problem.

However I dont see them printing anywhere.

What do I have to do to see these error messages?
A search with GOOGLE and a grep of the code wasnt too useful, but
it seems possible that I need to set

#define CONFIG_DEBUG

Is that true? I see a lot of <something>_DEBUGs in the .config file
but no simple CONFIG_DEBUG that is commented out.

In any case, how do I get these things to print?
--
Reg.Clemens
r...@dwf.com

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[Borislav Petkov]

From: r...@dwf.com
Date: Sat, Feb 27, 2010 at 03:11:03AM -0700

> Im looking at some kernel code, and there are 'pr_err' error messages in
> it that would help me discover my problem.
>
> However I dont see them printing anywhere.
>
> What do I have to do to see these error messages?

Take a look at 'ignore_loglevel' and 'loglevel' kernel parameters in
<Documentation/kernel-parameters.txt> depending on what exactly you want
to achieve.

> A search with GOOGLE and a grep of the code wasnt too useful, but
> it seems possible that I need to set
>
> #define CONFIG_DEBUG
>
> Is that true? I see a lot of <something>_DEBUGs in the .config file
> but no simple CONFIG_DEBUG that is commented out.

I think this is referring to pr_debug() calls. Those get called when you
add

#define DEBUG

to the file containing them. Otherwise they're optimized away.

--
Regards/Gruss,
Boris.