# [SOLVED]: WiFi gone after kernel upgrade

## ONEEYEMAN

Hi,

I recently updated my system and also updated my kernel from 3.12 to 4.1 (both gentoo-sources).

Unfortunately after the kernel upgrade I did lost the WiFi.

But when I rebooted to the old kernel (3.12), I got WiFi access again.

So, here are my logs:

Old dmesg can be found here

New dmesg can be found here

Does anyone see any differences?

Thank you.Last edited by ONEEYEMAN on Sat Jul 23, 2016 11:29 pm; edited 1 time in total

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## Hieronymus Bosch

Check your kernel configuration for both versions, maybe in 4.1 some options of the3.12 version are selected.

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## Jaglover

Both your links display 404 error.

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## ONEEYEMAN

New kernel config can be found here.

Old kernel config can be found here.

I tried to preserve the configuration wherever possible.

See any relevant differences?

Thank you.

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## chithanh

Maybe you can be a bit more specific than "lost the wifi".

Do you mean that the wifi adapter has disappeared from "lspci -k" or "ifconfig -a"?

Or do you just mean that legacy wireless extension tools like wicd don't recognize it as wifi any longer (this could be due to CONFIG_CFG80211_WEXT)

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## ONEEYEMAN

Hi, chithanh,

No, "lspci -v" still shows the driver. However, "ifconfig" does not show an IP for wlan0, not even an APIPA one (but I guess that's expected).

And I don't have a GUI yet - working on it as well with dantrell.

Also, like I said, rebooting into the old kernel - network access works fine.

Thank you.

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## chithanh

"no wifi" or "no network access", which one is it?

If wlan0 exists in "ifconfig -a" this usually means that your kernel has the correct driver. From "lspci -k" the "kernel driver in use" is important.

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## ONEEYEMAN

chithanh,

wlan0 does exist. "lspci -k" does show the same driver - "ath9k".

Also, are "no wifi" and "no network access" not the same?

I will repost the dmesg output when I come home from work tonight.

Thank you.

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## chithanh

"no wifi" would imply in my understanding that the wlan0 interface disappeared for whatever reason.  :Smile: 

Please also describe which method you use to connect to the wireless network.

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## ONEEYEMAN

chithanh,

Ok, I guess it does make sense.

I am connecting with "wpa_supplicant" which is set to run during the boot time.

Like I said before all I have right now is a Terminal. I am working to make working GNOME 3. So until this is resolved all I have is a nice black screen.  :Wink: 

Thank you.

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## chithanh

wpa_supplicant mean you use /etc/init.d/net.wlan0 /etc/wpa_supplicant/wpa_supplicant.conf and /etc/conf.d/net ? If so please post the latter here.

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## ONEEYEMAN

Yes, using all 3 of them.

Will post later when I'm at home.

Also, I would guess that they are all OK, since booting up the old kernel works fine and the connection is established.

Thank you.

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## ONEEYEMAN

Old dmesg.log can be found here

New dmesg.log can be found here

/etc/init.d/net.wlan0 can be found here

/etc/wpa_supplicant/wpa_supplicant.conf can be found here

/etc/conf.d/net can be found here

Hopefully all those will be good along with kernel configurations I posted earlier

Thank you.

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## chithanh

```
wpa_supplicant_wlan0="-Dwext -c/etc/wpa_supplicant/wpa_supplicant.conf"
```

That is your problem. You tell wpa_supplicant to use legacy wireless extensions through -Dwext, but your new kernel does not support them because you disabled CONFIG_CFG80211_WEXT.

You should switch to the modern cfg80211 framework by changing that to -Dnl80211

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## ONEEYEMAN

Thank you.

Switching to nl80211 resolved it.

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