I found that the problem is related to the location of my laptop! It might not be a Ubuntu related but (e.g. a hardware/environmental problem?), but, there are still hints that I think it is related to ubuntu:
1) the location difference is only relevant in my home, i.e. if I move the laptop out of this specific room it is ok. There is no problem if the laptop sits in another room, or brought to my office). 2) As I emphasised before, there is no problem with other devices in the same room 3) I plugged in a usb wifi adapter, which is recognized as wlan1, can be used without problem, although its signal level seems low (speed is ok). Info about the new usb wifi adapter (Buffalo) are: a) dmesg: [ 19.137557] ADDRCONF(NETDEV_UP): wlan1: link is not ready [ 19.137952] ADDRCONF(NETDEV_UP): wlan1: link is not ready [ 22.641581] wlan1: authenticate with 14:e6:e4:3b:d2:1e (try 1) [ 22.643452] wlan1: authenticated [ 22.709774] wlan1: associate with 14:e6:e4:3b:d2:1e (try 1) [ 22.713412] wlan1: RX AssocResp from 14:e6:e4:3b:d2:1e (capab=0x431 status=0 aid=2) [ 22.713419] wlan1: associated [ 22.713425] wlan1: No basic rates in AssocResp. Using min supported rate instead. [ 22.745064] ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready [ 32.965311] wlan1: no IPv6 routers present b) 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 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 09da:054f A4 Tech Co., Ltd Bus 002 Device 003: ID 0411:01a2 BUFFALO INC. (formerly MelCo., Inc.) WLI-UC-GNM Wireless LAN Adapter Bus 002 Device 004: ID 10f1:1a27 Importek c) syslog - attached. ** Attachment added: "syslog of wlan1" https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1000208/+attachment/3156777/+files/wlan1.log -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1000208 Title: wifi network get disconnected periodically Status in “network-manager” package in Ubuntu: Incomplete Bug description: I found a few similar bugs in launchpad history but they are at least 3-4 years old, and I encounter this problem just after upgrade to 12.04! I consulted a colleague who is a network expert, he suggested me to stop using wireless mouse, adjusted router settings, such as changed channels, added mac address binding, stopped ssid broadcasting, just in case there are some hackers trying to attack my network, but to no avail. Their are still possibilities of hardware configuration, environment issues or hackers around my house, but the most strange thing that triggered me reporting this bug is that all my other devices like windows laptop, android phones are all OK, only this Ubuntu laptop having problem! I also attach 2 files, one is the output of a ping command so that you can see what happened (during the ping session I tried to let network manager reconnect, even if it reconnected, the network is still not pingable. Another file is syslog about the network manager. ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: network-manager 0.9.4.0-0ubuntu4 ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14 Uname: Linux 3.2.0-24-generic x86_64 ApportVersion: 2.0.1-0ubuntu7 Architecture: amd64 Date: Wed May 16 20:47:46 2012 IfupdownConfig: auto lo iface lo inet loopback InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) IpRoute: default via 10.0.0.3 dev wlan0 proto static 10.0.0.0/24 dev wlan0 proto kernel scope link src 10.0.0.202 metric 2 169.254.0.0/16 dev wlan0 scope link metric 1000 NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true WimaxEnabled=true SourcePackage: network-manager UpgradeStatus: No upgrade log present (probably fresh install) nmcli-con: NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT READONLY DBUS-PATH Wired connection 1 1438463e-1c73-40f3-b17c-7e348b229da5 802-3-ethernet 1337172058 2012年05月16日 星期三 20时40分58秒 yes no /org/freedesktop/NetworkManager/Settings/1 MINGYANG 3cba4065-6d37-46ff-b35b-1f94b2bae5ba 802-11-wireless 1337172358 2012年05月16日 星期三 20时45分58秒 yes no /org/freedesktop/NetworkManager/Settings/0 nmcli-dev: DEVICE TYPE STATE DBUS-PATH wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/1 eth0 802-3-ethernet unavailable /org/freedesktop/NetworkManager/Devices/0 nmcli-nm: RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN running 0.9.4.0 connected enabled enabled enabled enabled disabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1000208/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
