Frequent WLAN disconnection in Ubuntu 12.04

Frequent WLAN disconnection in Ubuntu 12.04

I am getting random frequent Internet disconnection in Ubuntu 12.04. I don’t want to upgrade it. Since it is LTS version and also I have a lot of PPA packages installed. I don’t want to disturb the current development environment. I got a solution from askubuntu.com.

karthi@spark:~$ lsb_release -d
Description: Ubuntu 12.04.2 LTS
karthi@spark:~$ uname -mr
3.2.0-40-generic x86_64

Restarting network…

karthi@spark:~$ sudo /etc/init.d/networking restart
[sudo] password for karthi:
* Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces
* Reconfiguring network interfaces… [ OK ]
karthi@spark:~$ lspci
00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Ivy Bridge PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4)
00:1c.3 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 4 (rev c4)
00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04)
01:00.0 3D controller: NVIDIA Corporation Device 1140 (rev a1)
02:00.0 Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)

 

karthi@spark:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 002: ID 18d1:4e44 Google Inc.
Bus 003 Device 006: ID 18d1:4ee2 Google Inc.
Bus 003 Device 004: ID 046d:c52f Logitech, Inc. Wireless Mouse M305
Bus 002 Device 003: ID 8087:07da Intel Corp.
Bus 002 Device 004: ID 2232:1018

 

Interface config.

karthi@spark:~$ ifconfig
eth0 Link encap:Ethernet HWaddr e8:03:9a:af:12:52
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:43 Base address:0x4000

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:16436 Metric:1
RX packets:12975 errors:0 dropped:0 overruns:0 frame:0
TX packets:12975 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1679882 (1.6 MB) TX bytes:1679882 (1.6 MB)

wlan0 Link encap:Ethernet HWaddr c4:85:08:13:d8:14
inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::c685:8ff:fe13:d814/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:98351 errors:0 dropped:0 overruns:0 frame:0
TX packets:89435 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:84160670 (84.1 MB) TX bytes:17928000 (17.9 MB)

karthi@spark:~$ iwconfig
lo no wireless extensions.

wlan0 IEEE 802.11abgn ESSID:”feaws”
Mode:Managed Frequency:2.437 GHz Access Point: 4C:60:DE:42:73:A5
Bit Rate=1 Mb/s Tx-Power=15 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=70/70 Signal level=-24 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:76 Invalid misc:70 Missed beacon:0

eth0 no wireless extensions.

 

karthi@spark:~$ dmesg|grep “wlan”
[ 27.728154] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 27.728392] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 35.376629] wlan0: authenticate with 4c:60:de:42:73:a5 (try 1)
[ 35.379454] wlan0: authenticated
[ 35.388059] wlan0: associate with 4c:60:de:42:73:a5 (try 1)
[ 35.394106] wlan0: RX AssocResp from 4c:60:de:42:73:a5 (capab=0x411 status=0 aid=1)
[ 35.394110] wlan0: associated
[ 35.398940] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 46.153753] wlan0: no IPv6 routers present
[ 226.521790] wlan0: deauthenticating from 4c:60:de:42:73:a5 by local choice (reason=3)
[ 235.528773] wlan0: authenticate with 4c:60:de:42:73:a5 (try 1)
[ 235.531631] wlan0: authenticated
[ 235.532677] wlan0: associate with 4c:60:de:42:73:a5 (try 1)
[ 235.536559] wlan0: RX ReassocResp from 4c:60:de:42:73:a5 (capab=0x411 status=0 aid=1)
[ 235.536569] wlan0: associated
[ 245.846753] wlan0: no IPv6 routers present
[11815.342871] wlan0: deauthenticating from 4c:60:de:42:73:a5 by local choice (reason=3)
[11829.945529] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[11837.566308] wlan0: authenticate with 4c:60:de:42:73:a5 (try 1)
[11837.569639] wlan0: authenticated
[11837.570146] wlan0: associate with 4c:60:de:42:73:a5 (try 1)
[11837.573983] wlan0: RX AssocResp from 4c:60:de:42:73:a5 (capab=0x411 status=0 aid=3)
[11837.573993] wlan0: associated
[11837.597218] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[11847.916449] wlan0: no IPv6 routers present

 

karthi@spark:~$ iwlist scan
lo Interface doesn’t support scanning.

wlan0 Scan completed :
Cell 01 – Address: 4C:60:DE:42:73:A5
Channel:6
Frequency:2.437 GHz (Channel 6)
Quality=70/70 Signal level=-24 dBm
Encryption key:on
ESSID:”feaws”
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
24 Mb/s; 36 Mb/s; 54 Mb/s
Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 48 Mb/s
Mode:Master
Extra:tsf=000000031071319a
Extra: Last beacon: 4080ms ago
IE: Unknown: 00056665617773
IE: Unknown: 010882840B162430486C
IE: Unknown: 030106
IE: Unknown: 2A0100
IE: Unknown: 2F0100
IE: Unknown: 32040C121860
IE: Unknown: 2D1A6C181BFF00000000000000000000000000000000000000000000
IE: Unknown: 3D1606001300000000000000000000000000000000000000
IE: Unknown: 4A0E14000A002C01C800140005001900
IE: Unknown: 7F0101
IE: Unknown: DD050050F20500
IE: Unknown: DD7F0050F204104A00011010440001021041000100103B000103104700106FBF711962A0377782F7605E8E2D377D1021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084
IE: Unknown: DD090010180202F0050000
IE: Unknown: DD180050F2020101800003A4000027A4000042435E0062322F00
IE: Unknown: DD1E00904C336C181BFF00000000000000000000000000000000000000000000
IE: Unknown: DD1A00904C3406001300000000000000000000000000000000000000

eth0 Interface doesn’t support scanning.

 

Got solution from Askubuntu.com

Try these

sudo modprobe -rfv ath9k

sudo modprobe -v ath9k nohwcrypt=1

If this works, add these lines to /etc/rc.local

or create (or edit)  /etc/modprobe.d/ath9k.conf and add

options ath9k nohwcrypt=1

 

 

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