1

The Problem:

I have a dual boot setup with Windows 7 and Ubuntu 14.04. Everything was working fine until yesterday morning after login I couldn't get the wifi in ubuntu stopped to work (see details below) the windows part seems to work just fine. I would like to restore the wifi in ubuntu.

Some Background:

The last time everything was fine, I was trying to (unsuccessfully) install haskell-platform in ubuntu (see here ). I followed the advice here and downgraded my libgl1-mesa-glx package. As a result some brutal changes took place and I had to reinstall Xorg and Desktop-Environment. The problem with network manager started after that so I am guessing this was the source.

As mentioned before, I can access wifi via Windows. I can also access wifi by using a live ubuntu-usb. So, I can install packages to my hdd-ubuntu distribution. This makes me believe that there is no hardware problem and somehow I have deleted some essential packages.

I am a noob in networking issues so most of what I have done (outlined below) is based on my very limited (and perhaps wacky) understanding and reading through many threads on this site and elsewhere. So it is entirely possible that I have missed something trivial.

What I did

I purged and then reinstalled the packages network-manager, resolvconf; isc-dhcp-client and isc-dhcp-server packages couple of times.

This doesn't seem to solve the problem.

My ifconfig -a reads:

eth0 Link encap:Ethernet HWaddr 78:45:c4:b6:b4:85
UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:17

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:27488 errors:0 dropped:0 overruns:0 frame:0 TX packets:27488 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2028140 (2.0 MB) TX bytes:2028140 (2.0 MB)

virbr0 Link encap:Ethernet HWaddr 3e:e3:92:b9:ab:c6
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

wlan0 Link encap:Ethernet HWaddr 08:3e:8e:04:2f:9f
UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

lshw -C shows

 

*-network description: Wireless interface product: AR9485 Wireless Network Adapter vendor: Qualcomm Atheros physical id: 0 bus info: pci@0000:07:00.0 logical name: wlan0 version: 01 serial: 08:3e:8e:04:2f:9f width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.13.0-77-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:19 memory:f7d00000-f7d7ffff memory:f7d80000-f7d8ffff *-network description: Ethernet interface product: AR8162 Fast Ethernet vendor: Qualcomm Atheros physical id: 0 bus info: pci@0000:09:00.0 logical name: eth0 version: 10 serial: 78:45:c4:b6:b4:85 capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm pciexpress msi msix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=alx latency=0 link=no multicast=yes port=twisted pair resources: irq:47 memory:f7c00000-f7c3ffff ioport:e000(size=128)


Some other configuration files that I checked were :/etc/network/interfaces which reads

auto lo iface lo inet loopback

I added and then commented out #auto eth0, #iface eth0 inet dhcp, #auto wlan0, #iface wlan0 inet dhcp because it didn't solve the problem and just started the message waiting for network configuration when booting into ubuntu.

My /etc/resolv.conf reads

#Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) #DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.1.1 nameserver 8.8.8.8

My /etc/hosts reads

 

127.0.0.1 localhost 127.0.1.1 my-comp #The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters

and my /etc/NetworkManager/NetworkManager.conf reads

 

[main] plugins=ifupdown,keyfile,ofono dns=dnsmasq

[ifupdown] managed=false

My iwconfig outputs:


wlan0     IEEE 802.11bgn  ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=16 dBm
Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off

If tried `sudo ifdown wlan0' and 'sudo ifup wlan0' and didn't get any output which makes me think they are ok.

I am looking for any directions that I might take to solve the problem. One possible way out, I think, is to try to transfer all relevant packages from live-usb to my home folder but I am not sure how to go about it.... I would prefer any solution short of a fresh install at this point.

Thank you for your help in advance (and special thanks for any impromptu networking lessons too). I would be happy to put any additional information.


Edit

Some additional info based on answers/comments.

rfkill list output


0: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
1: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

0

I believe you soft blocked WiFi by accident to check that run

rfkill list

You there see a list of all wireless devices (wifi, Bluetooth) if you see a soft blocked: yes you should run

sudo rfkill unblock wifi

And you should be fine

  • Thank you for the answer. I ran rfkill list and the output didn't indicate a soft-block. I have updated the out put in the question. – DBS Jan 30 '16 at 23:21
0

A million thanks to this question here the problem is a bug in libnl package (see here for details ).

I do not claim any credit for this answer. I am posting it because I myself wasn't aware of this issue (and erroneously thought that the reason was something else) so people doing google search on wifi issues on ubuntu maynot get directed to that question but they might benefit from the solution .

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