I do encounter the same problem here with xubuntu 15.04 on my Dell Latitude 430 quite frequently.
Looking at my syslog messages, this situation always seems to start with the following output: Jun 6 20:35:39 smithers kernel: [ 4126.496072] iwl3945 0000:0c:00.0: Error sending C_POWER_TBL: time out after 500ms. Jun 6 20:35:39 smithers kernel: [ 4126.496086] iwl3945 0000:0c:00.0: set power fail, ret = -110 Jun 6 20:35:41 smithers kernel: [ 4128.472071] iwl3945 0000:0c:00.0: Queue 4 stuck for 2500 ms. Jun 6 20:35:41 smithers kernel: [ 4128.472082] iwl3945 0000:0c:00.0: On demand firmware reload Jun 6 20:35:41 smithers kernel: [ 4128.508118] ieee80211 phy0: Hardware restart was requested Jun 6 20:35:41 smithers kernel: [ 4128.560704] iwl3945 0000:0c:00.0: BSM uCode verification failed at addr 0x00003800+0 (of 900), is 0xa5a5a5a2, s/b 0xf802020 Jun 6 20:35:41 smithers kernel: [ 4128.560715] iwl3945 0000:0c:00.0: Unable to set up bootstrap uCode: -5 [ the last two lines are repeated 5 times ] Jun 6 20:35:41 smithers kernel: [ 4128.786187] iwl3945 0000:0c:00.0: Unable to initialize device after 5 attempts. Jun 6 20:35:41 smithers kernel: [ 4128.786198] ------------[ cut here ]------------ Jun 6 20:35:41 smithers kernel: [ 4128.786267] WARNING: CPU: 0 PID: 2505 at /build/buildd/linux-3.19.0/net/mac80211/util.c:1774 ieee80211_reconfig+0x47d/0x1480 [mac80211]() Jun 6 20:35:41 smithers kernel: [ 4128.786271] Hardware became unavailable during restart. Jun 6 20:35:41 smithers kernel: [ 4128.786275] Modules linked in: [ removed to shorten post ] Jun 6 20:35:41 smithers kernel: [ 4128.786389] CPU: 0 PID: 2505 Comm: kworker/0:0 Not tainted 3.19.0-18-generic #18-Ubuntu Jun 6 20:35:41 smithers kernel: [ 4128.786393] Hardware name: Dell Inc. Latitude D430 /0XW631, BIOS A00 05/21/2007 Jun 6 20:35:41 smithers kernel: [ 4128.786419] Workqueue: events ieee80211_restart_work [mac80211] [ register dump removed to shorten post ] Jun 6 20:35:41 smithers kernel: [ 4128.786457] Call Trace: [ call trace removed to shorten post] [ A really large number of such dumps follows ] Jun 6 20:35:42 smithers kernel: [ 4128.803212] ---[ end trace eb90e628c7fb6207 ]--- Jun 6 20:35:42 smithers kernel: [ 4128.804736] cfg80211: Calling CRDA to update world regulatory domain Jun 6 20:35:44 smithers kernel: [ 4131.825741] cfg80211: World regulatory domain updated: Jun 6 20:35:44 smithers kernel: [ 4131.825748] cfg80211: DFS Master region: unset Jun 6 20:35:44 smithers kernel: [ 4131.825753] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time) Jun 6 20:35:44 smithers kernel: [ 4131.825759] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A) Jun 6 20:35:44 smithers kernel: [ 4131.825764] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A) Jun 6 20:35:44 smithers kernel: [ 4131.825769] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm), (N/A) Jun 6 20:35:44 smithers kernel: [ 4131.825774] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A) Jun 6 20:35:44 smithers kernel: [ 4131.825778] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A) Jun 6 20:35:45 smithers dhclient: receive_packet failed on wlan0: Network is down Jun 6 20:31:40 smithers wpa_supplicant[1041]: message repeated 7 times: [ wlan0: WPA: Group rekeying completed with 64:7c:34:a6:33:e8 [GTK=TKIP]] Jun 6 20:35:45 smithers wpa_supplicant[1041]: wlan0: CTRL-EVENT-DISCONNECTED bssid=64:7c:34:a6:33:e8 reason=3 locally_generated=1 -- 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/1408963 Title: [Xbuntu 14.04, 14.10 and 15.04] Network manager stops working: iwl3945 0000:03:00.0: BSM uCode verification failed at addr ...; wlan0: deauthenticating from... by local choice (Reason: 3=DEAUTH_LEAVING), Status in linux-firmware package in Ubuntu: Confirmed Status in network-manager package in Ubuntu: Confirmed Bug description: From time to time, the system loses all wireles networks and kubuntu network manager applet goes blank - not even one network is shown. All wifi connections are broken. Rebooting fixes the issue, switching to WICD on-the-fly enables to continue browsing without rebooting, so it seems to be no hardware issue or iwl3945 issue. What to expect: stable connections and flawless network managing. What happens: so above. Further informations about the system, the network configuration, the package version can be found in the attachment, also parts of rsyslog and dmesg. Interesting, according to some helpers, are the following lines: dmesg: wlan0: deauthenticating from 02:26:4d:ac:8f:45 by local choice (Reason: 3=DEAUTH_LEAVING) lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 14.10 Release: 14.10 Codename: utopic apt-cache policy network-manager network-manager: Installiert: 0.9.8.8-0ubuntu28 Installationskandidat: 0.9.8.8-0ubuntu28 Versionstabelle: *** 0.9.8.8-0ubuntu28 0 500 http://de.archive.ubuntu.com/ubuntu/ utopic/main amd64 Packages 100 /var/lib/dpkg/status To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/1408963/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp