# [solved] dmesg output is empty

## kgraysiue80

Hello everyone,

I recently upgraded to kernel- 2.6.12-gentoo-r6 and now my dmesg output is empty.  I don't even know where to start trying to figure this out.  If you have any ideas or need more information, please let me know.  I am running an athlon64 in 64 bit mode.

Thanks

kgraysiue80Last edited by kgraysiue80 on Mon Aug 08, 2005 1:07 am; edited 1 time in total

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## xoomix

At the very bottom of /etc/init.d/bootmisc should be an entry like so:

        #

        # Create an 'after-boot' dmesg log

        #

        touch /var/log/dmesg

        chmod 640 /var/log/dmesg

        dmesg > /var/log/dmesg

Do you have that entry? Also that should be added with rc-update add bootmisc boot -- check those things and post back.

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## widan

 *kgraysiue80 wrote:*   

> now my dmesg output is empty

 

Could you run those (either one should do, but the first one can fail depending on your kernel config) and post the output ?

```
zgrep PRINTK /proc/config.gz

grep PRINTK /usr/src/linux/.config
```

There are a few people who found themselves with printk support disabled for some unknown reason, and the symptom was (quite logically) a blank dmesg.

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## kgraysiue80

thank you,

I enabled the options in the kernel and now I have dmesg output.

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## kueitao

 *widan wrote:*   

> 
> 
> There are a few people who found themselves with printk support disabled for some unknown reason, and the symptom was (quite logically) a blank dmesg.
> 
> 

 

This can happen because some people set "General Setup" -> "Configure standard kernel features" that doesn't do anything special but it prompts for a few more options that never must be changed except you have special hardware requirements as those for embedded systems.

So none should set the above-mentioned option because then he/she would have to do with some esoteric configuration issues that the mere removing of support for printk is the only one that wouldn't kill your box! Leave them in the hands of embedded system engineers and kernel hackers (developers).

The proper fix in order to have printk working is deselecting "Configure standard kernel features". In doing so printk is automatically re-enabled and every possible other wrong selection is fixed up.

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