# Kernel build failure.



## manobrow (Feb 19, 2009)

My kernel failed compilation during the link stage because of some undefined references to ieee80211 functions. I am guessing that this is because I commented out some components that I didn't think I need. How do I know which components in my kernel config depend which others?
Thank you.


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## Lowell (Feb 19, 2009)

Usually, it's pretty obvious; for example, any 802.11 device still in your configuration will require the wlan device, and probably some of the other wlan_* devices as well.

Otherwise, there's often a comment to warn you.


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## ale (Feb 19, 2009)

You may also try looking into the following files:
/usr/src/sys/conf/NOTES
/usr/src/sys/`uname -m`/conf/NOTES


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## SeanC (Mar 11, 2009)

manobrow said:
			
		

> I am guessing that this is because I commented out some components that I didn't think I need.



Check the output of *dmesg* right after boot. Everything that you need to keep in your custom kernel _should_ be listed there.


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## manobrow (Mar 11, 2009)

Thanks go to everyone who tried to help. I feel I must apologize for forgetting to inform you that I got over the issue


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## ale (Mar 11, 2009)

manobrow said:
			
		

> Thanks go to everyone who tried to help. I feel I must apologize for forgetting to inform you that I got over the issue


It would be nice for the other members and for who is facing the same problem to know how.


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## SeanC (Mar 11, 2009)

And tag the thread as *solved*.


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## manobrow (Mar 13, 2009)

I removed some more lines related to the wireless that I had missed the first time. Nothing fancy.


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