[lfs-support] Ethernet Card Not Found

Alan Feuerbacher alanf00 at comcast.net
Mon Nov 25 17:19:00 PST 2013

On 11/25/2013 11:27 AM, Dan McGhee wrote:
> Alan, you have gotten a number of great suggestions from some really
> helpful people.  I think, however, that the waters are very muddy right
> now.  The main problem is that your system can't find your ethernet
> card--eth0.  That's the first goal.  After your system sees and
> acknowledges it's existence, then troubleshoot connecting if any
> problems persist.

By now you'll have seen that I've gotten the card to work, thanks to all 
you kind experts.

>>>>> lsmod
>>>>> ######
>>>>> Module                  Size    Used by
>>>>> x86_pkg_temp_thermal    4511    0
>>>>> ######

> This shows that either the module is not loaded or that it's configured
> into your kernel.

Having gotten the card to work, I repeated "lsmod" and got exactly the 
same result as above.

>>> I think Bruce was talking about a working distribution (the one you used to
>>> build LFS for example). Boot it and run lsmod.
>>> The information you get there could indicate the right driver for the kernel.
>> Ah! Here's the output from the Fedora host with lsmod :
>> #######
>> Module                  Size  Used by
>> <snipped irrelevant stuff>
>> mac80211              564847  1 b43
>> cfg80211              460310  2 b43,mac80211
>> rfkill                 21694  5 cfg80211,bluetooth,asus_wmi [This may be only for wireless.  I don't know.]
>> r8169                  71677  0
>> mii                    13527  1 r8169

> This shows you the modules Fedora uses to get your card working.

My suspicion is that the modules aside from r8169 are not applicable to 
getting the card working. See below.

> To see what might be happening to your ethernet card when LFS boots, run
> <dmesg | grep Ethernet>
> Here are the results I get:
>>   r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
>>   Bluetooth: BNEP (Ethernet Emulation) ver 1.3
> I left that second line it to show you that you might get a number of
> lines.  But the one you're looking for is the first one.  You and I have
> the same card.

I got this:

[    0.617753] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded

> If this doesn't show up, your system somehow does not recognize, can't
> or won't load the driver.  Please refer back to the results of 'lsmod'
> from your Fedora distro.  You need "mac80211", "cfg80211" and "mii" in
> addition to "r8169".  It wouldn't hurt to make sure that rfkill is
> available.  Since we have the same card, I know that yours also supports
> bluetooth and that utilizes "rfkill."

I know that one can install bluetooth software, but I have not done so.

> So now you know that you need
> "CONFIG_{MAC80211,CFG80211,MII,RFKILL,R8169}=y or m in your kernel
> .config.

Those variables are all set =y in my .config.

Based on the fact that my ethernet card is working (I know this because 
I can ping websites like Google, "ping", and it returns 
something sensible) I have to conclude that those other modules are not 
relevant to the card. At least, not for getting its base function 
running. Any ideas?

 > A really easy way to check this is to use <cat -n [config file
> name] | grep SOMETHING>.  The caps are important. For example, here are
> my results from <cat -n /boot/config-3.10.10 | grep R8169>:
>> 1843    CONFIG_R8169=m
> That reveals what line it's on <cat -n> and how it's set.  You then have
> to merely open the file in an editor and go to that line if you want to
> change it.  Use <grep> to find all the instances of 80211 and the
> others, make any changes you need to and reboot.

Thank you! You've expanded my nerdy horizons!

> FWIW, work on getting eth0 recognized first.  Configure it just like the
> LFS book says and don't worry what Fedora calls it. iptables and routing
> aren't going to help you if your system doesn't see your card.

I'm not far enough along on the road to Linux Expert to know what those 
things are. :-)

> In my estimation 'dmesg,' 'cat -n,' 'lsmod,' 'lspci,' and 'grep' are
> indispensable troubleshooting tools.

Yes! Along with lsblk, blkid, fdisk, gdisk, lspci, etc. that I've become 
far more aware of recently.


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