sounds like a kernel bug (oh, gosh, lord have mercy on us) Zappy, can you please test the Ubuntu mainline kernel and see if you can reproduce it there?
** Package changed: network-manager (Ubuntu) => linux (Ubuntu) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1315470 Title: wlan0 gets disconnected randomly and can not reconnect Status in linux package in Ubuntu: Confirmed Bug description: At random times, several time sper day after upgrade from 13.10 to 14.04, my wireless connection gets disconnected and the system log shows: May 2 13:17:01 Baba-Yaga CRON[18205]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) May 2 13:40:03 Baba-Yaga wpa_supplicant[1553]: wlan0: CTRL-EVENT-DISCONNECTED bssid=d4:ca:6d:57:91:d1 reason=0 May 2 13:40:03 Baba-Yaga NetworkManager[1200]: <info> (wlan0): roamed from BSSID D4:CA:6D:57:91:D1 (Host) to (none) ((none)) May 2 13:40:03 Baba-Yaga NetworkManager[1200]: <info> (wlan0): supplicant interface state: completed -> disconnected May 2 13:40:03 Baba-Yaga wpa_supplicant[1553]: wlan0: Reject scan trigger since one is already pending May 2 13:40:03 Baba-Yaga wpa_supplicant[1553]: wlan0: Failed to initiate AP scan At this point, I will never be able to reconnect to the access point and after several attempts, the wirless connection is removed from the NetworkManager applet and the only way to get the wirless connection back, is to shut down the machine, turn it back on and let it boot. Just doing a warm reboot will not resolve the issue in many cases. A cold reboot always will. This is a Realtek USB based WiFi device and I have used it now for a few years without issues. Moving the WiFi device to a Windows PC shows that it works as intended and is never disconnecting or losing connection in any way. lsusb shows: Bus 001 Device 005: ID 0bda:8171 Realtek Semiconductor Corp. RTL8188SU 802.11n WLAN Adapter $ lsb_release -rd Description: Ubuntu 14.04 LTS Release: 14.04 $ uname -a Linux Baba-Yaga 3.14.0-031400-generic #201403310035 SMP Mon Mar 31 04:36:23 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux Same issue is also present with the default 3.13 kernel. $ apt-cache policy network-manager network-manager: Installed: 0.9.8.8-0ubuntu7 Candidate: 0.9.8.8-0ubuntu7 Version table: *** 0.9.8.8-0ubuntu7 0 500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages 100 /var/lib/dpkg/status ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: network-manager 0.9.8.8-0ubuntu7 Uname: Linux 3.14.0-031400-generic x86_64 ApportVersion: 2.14.1-0ubuntu3 Architecture: amd64 Date: Fri May 2 14:04:32 2014 EcryptfsInUse: Yes ExecutablePath: /usr/sbin/NetworkManager InstallationDate: Installed on 2014-04-26 (5 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Beta amd64 (20140326) IpRoute: default via 192.168.100.1 dev wlan0 proto static 169.254.0.0/16 dev eth0 scope link metric 1000 169.254.136.0/24 dev eth0 proto kernel scope link src 169.254.136.2 192.168.100.0/24 dev wlan0 proto kernel scope link src 192.168.100.162 metric 9 NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true WimaxEnabled=true ProcEnviron: TERM=linux PATH=(custom, no user) LANG=en_US.UTF-8 RfKill: SourcePackage: network-manager UpgradeStatus: No upgrade log present (probably fresh install) nmcli-con: NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT READONLY DBUS-PATH Suburban 069407c8-4892-4a35-ae60-67471e4b941c 802-11-wireless 1399053730 Fri 02 May 2014 02:02:10 PM EDT yes no /org/freedesktop/NetworkManager/Settings/1 Auto Suburban 1 31b75b94-c201-404c-9b8a-38a3d63fd032 802-11-wireless 0 never yes no /org/freedesktop/NetworkManager/Settings/0 nmcli-dev: DEVICE TYPE STATE DBUS-PATH eth0 802-3-ethernet unmanaged /org/freedesktop/NetworkManager/Devices/1 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/0 nmcli-nm: RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN running 0.9.8.8 connected enabled enabled enabled enabled disabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1315470/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp