Hi Guys, i'm facing same problem BCM43142 driver is crashing i already open bug but so far i didn't get necessary help to resolve the issue, I faced the same problem in ubuntu 14.04 so upgraded to ubuntu 16.04 but still my wifi chipset connects and disconnects after some time, please check the crash log, [ 69.780612] usb 1-1.4: new full-speed USB device number 4 using ehci-pci [ 69.875757] usb 1-1.4: New USB device found, idVendor=0a5c, idProduct=21d7 [ 69.875763] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 69.875767] usb 1-1.4: Product: BCM43142A0 [ 69.875770] usb 1-1.4: Manufacturer: Broadcom Corp [ 69.875772] usb 1-1.4: SerialNumber: 9C2A70D0CA3A [ 70.196820] Bluetooth: Core ver 2.21 [ 70.196840] NET: Registered protocol family 31 [ 70.196841] Bluetooth: HCI device and connection manager initialized [ 70.196845] Bluetooth: HCI socket layer initialized [ 70.196847] Bluetooth: L2CAP socket layer initialized [ 70.196852] Bluetooth: SCO socket layer initialized [ 70.596642] usbcore: registered new interface driver btusb [ 70.603752] Bluetooth: hci0: BCM: chip id 70 [ 70.619654] Bluetooth: hci0: BCM43142A [ 70.619664] Bluetooth: hci0: BCM (001.001.011) build 0000 [ 70.652707] bluetooth hci0: Direct firmware load for brcm/BCM.hcd failed with error -2 [ 70.652714] Bluetooth: hci0: BCM: Patch brcm/BCM.hcd not found [ 72.656604] Bluetooth: hci0 command 0x1003 tx timeout [ 73.450154] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 73.450158] Bluetooth: BNEP filters: protocol multicast [ 73.450164] Bluetooth: BNEP socket layer initialized [ 73.651455] Bluetooth: RFCOMM TTY layer initialized [ 73.651465] Bluetooth: RFCOMM socket layer initialized [ 73.651471] Bluetooth: RFCOMM ver 1.11 [ 288.406323] ------------[ cut here ]------------ [ 288.406349] WARNING: CPU: 2 PID: 439 at /build/linux-R0TiM8/linux-4.4.0/net/wireless/sme.c:850 cfg80211_roamed+0x86/0xa0 [cfg80211]() [ 288.406350] Modules linked in: rfcomm bnep btusb btrtl btbcm btintel bluetooth binfmt_misc nls_iso8859_1 wl(POE) snd_hda_codec_hdmi snd_hda_codec_cirrus snd_hda_codec_generic snd_hda_intel snd_hda_codec uvcvideo snd_hda_core intel_rapl videobuf2_vmalloc videobuf2_memops x86_pkg_temp_thermal intel_powerclamp videobuf2_v4l2 videobuf2_core coretemp v4l2_common snd_hwdep kvm_intel snd_pcm videodev snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq media snd_seq_device snd_timer dell_wmi mei_me sparse_keymap kvm cfg80211 snd mei dell_laptop irqbypass crct10dif_pclmul dcdbas dell_smm_hwmon input_leds crc32_pclmul shpchp serio_raw soundcore cryptd mac_hid lpc_ich parport_pc ppdev lp parport autofs4 ums_realtek uas usb_storage i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect ahci sysimgblt fb_sys_fops [ 288.406388] libahci drm psmouse r8169 mii wmi video fjes [ 288.406395] CPU: 2 PID: 439 Comm: wl_event_handle Tainted: P OE 4.4.0-38-generic #57-Ubuntu [ 288.406396] Hardware name: Dell Inc. Vostro 2520/0V1NDP, BIOS A11 02/24/2014 [ 288.406398] 0000000000000286 00000000ff0b74b0 ffff8800d5f4fdc8 ffffffff813f1b73 [ 288.406401] 0000000000000000 ffffffffc0375bd0 ffff8800d5f4fe00 ffffffff810811c2 [ 288.406403] ffff8800ce8d7000 ffff880119385b40 0000000000000099 ffff880119385cc0 [ 288.406405] Call Trace: [ 288.406412] [] dump_stack+0x63/0x90 [ 288.406416] [] warn_slowpath_common+0x82/0xc0 [ 288.406418] [] warn_slowpath_null+0x1a/0x20 [ 288.406432] [] cfg80211_roamed+0x86/0xa0 [cfg80211] [ 288.406471] [] wl_notify_roaming_status+0xc5/0x140 [wl] [ 288.406505] [] wl_event_handler+0x60/0x1d0 [wl] [ 288.406538] [] ? wl_notify_scan_status+0x320/0x320 [wl] [ 288.406540] [] kthread+0xd8/0xf0 [ 288.406543] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 288.406546] [] ret_from_fork+0x3f/0x70 [ 288.406548] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 288.406549] ---[ end trace 91e2975807f31653 ]--- [ 294.360385] cfg80211: World regulatory domain updated: [ 294.360389] cfg80211: DFS Master region: unset [ 294.360390] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time) [ 294.360392] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A) [ 294.360394] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A) [ 294.360395] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm), (N/A) [ 294.360397] cfg80211: (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A) [ 294.360399] cfg80211: (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s) [ 294.360401] cfg80211: (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm), (0 s) [ 294.360402] cfg80211: (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A) [ 294.360403] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm), (N/A) [ 296.393069] ------------[ cut here ]------------ [ 296.393109] WARNING: CPU: 1 PID: 439 at /build/linux-R0TiM8/linux-4.4.0/net/wireless/sme.c:850 cfg80211_roamed+0x86/0xa0 [cfg80211]() [ 296.393112] Modules linked in: rfcomm bnep btusb btrtl btbcm btintel bluetooth binfmt_misc nls_iso8859_1 wl(POE) snd_hda_codec_hdmi snd_hda_codec_cirrus snd_hda_codec_generic snd_hda_intel snd_hda_codec uvcvideo snd_hda_core intel_rapl videobuf2_vmalloc videobuf2_memops x86_pkg_temp_thermal intel_powerclamp videobuf2_v4l2 videobuf2_core coretemp v4l2_common snd_hwdep kvm_intel snd_pcm videodev snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq media snd_seq_device snd_timer dell_wmi mei_me sparse_keymap kvm cfg80211 snd mei dell_laptop irqbypass crct10dif_pclmul dcdbas dell_smm_hwmon input_leds crc32_pclmul shpchp serio_raw soundcore cryptd mac_hid lpc_ich parport_pc ppdev lp parport autofs4 ums_realtek uas usb_storage i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect ahci sysimgblt fb_sys_fops [ 296.393168] libahci drm psmouse r8169 mii wmi video fjes [ 296.393178] CPU: 1 PID: 439 Comm: wl_event_handle Tainted: P W OE 4.4.0-38-generic #57-Ubuntu [ 296.393181] Hardware name: Dell Inc. Vostro 2520/0V1NDP, BIOS A11 02/24/2014 [ 296.393184] 0000000000000286 00000000ff0b74b0 ffff8800d5f4fdc8 ffffffff813f1b73 [ 296.393188] 0000000000000000 ffffffffc0375bd0 ffff8800d5f4fe00 ffffffff810811c2 [ 296.393192] ffff8800ce8d7000 ffff8800d6077b40 0000000000000099 ffff8800d6077d80 [ 296.393195] Call Trace: [ 296.393205] [] dump_stack+0x63/0x90 [ 296.393211] [] warn_slowpath_common+0x82/0xc0 [ 296.393215] [] warn_slowpath_null+0x1a/0x20 [ 296.393240] [] cfg80211_roamed+0x86/0xa0 [cfg80211] [ 296.393316] [] wl_notify_roaming_status+0xc5/0x140 [wl] [ 296.393379] [] wl_event_handler+0x60/0x1d0 [wl] [ 296.393439] [] ? wl_notify_scan_status+0x320/0x320 [wl] [ 296.393445] [] kthread+0xd8/0xf0 [ 296.393449] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 296.393454] [] ret_from_fork+0x3f/0x70 [ 296.393457] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 296.393460] ---[ end trace 91e2975807f31654 ]--- [ 307.760955] ------------[ cut here ]------------ [ 307.760981] WARNING: CPU: 2 PID: 439 at /build/linux-R0TiM8/linux-4.4.0/net/wireless/sme.c:850 cfg80211_roamed+0x86/0xa0 [cfg80211]() [ 307.760982] Modules linked in: rfcomm bnep btusb btrtl btbcm btintel bluetooth binfmt_misc nls_iso8859_1 wl(POE) snd_hda_codec_hdmi snd_hda_codec_cirrus snd_hda_codec_generic snd_hda_intel snd_hda_codec uvcvideo snd_hda_core intel_rapl videobuf2_vmalloc videobuf2_memops x86_pkg_temp_thermal intel_powerclamp videobuf2_v4l2 videobuf2_core coretemp v4l2_common snd_hwdep kvm_intel snd_pcm videodev snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq media snd_seq_device snd_timer dell_wmi mei_me sparse_keymap kvm cfg80211 snd mei dell_laptop irqbypass crct10dif_pclmul dcdbas dell_smm_hwmon input_leds crc32_pclmul shpchp serio_raw soundcore cryptd mac_hid lpc_ich parport_pc ppdev lp parport autofs4 ums_realtek uas usb_storage i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect ahci sysimgblt fb_sys_fops [ 307.761017] libahci drm psmouse r8169 mii wmi video fjes [ 307.761023] CPU: 2 PID: 439 Comm: wl_event_handle Tainted: P W OE 4.4.0-38-generic #57-Ubuntu [ 307.761024] Hardware name: Dell Inc. Vostro 2520/0V1NDP, BIOS A11 02/24/2014 [ 307.761026] 0000000000000286 00000000ff0b74b0 ffff8800d5f4fdc8 ffffffff813f1b73 [ 307.761028] 0000000000000000 ffffffffc0375bd0 ffff8800d5f4fe00 ffffffff810811c2 [ 307.761030] ffff8800ce8d7000 ffff880119385900 0000000000000099 ffff880119385600 [ 307.761032] Call Trace: [ 307.761038] [] dump_stack+0x63/0x90 [ 307.761041] [] warn_slowpath_common+0x82/0xc0 [ 307.761043] [] warn_slowpath_null+0x1a/0x20 [ 307.761056] [] cfg80211_roamed+0x86/0xa0 [cfg80211] [ 307.761091] [] wl_notify_roaming_status+0xc5/0x140 [wl] [ 307.761121] [] wl_event_handler+0x60/0x1d0 [wl] [ 307.761150] [] ? wl_notify_scan_status+0x320/0x320 [wl] [ 307.761152] [] kthread+0xd8/0xf0 [ 307.761154] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 307.761157] [] ret_from_fork+0x3f/0x70 [ 307.761159] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 307.761160] ---[ end trace 91e2975807f31655 ]--- [ 913.376047] cfg80211: World regulatory domain updated: [ 913.376051] cfg80211: DFS Master region: unset [ 913.376052] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time) [ 913.376055] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A) [ 913.376056] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A) [ 913.376058] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm), (N/A) [ 913.376059] cfg80211: (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A) [ 913.376061] cfg80211: (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s) [ 913.376063] cfg80211: (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm), (0 s) [ 913.376064] cfg80211: (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A) [ 913.376065] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm), (N/A) [ 915.196072] ------------[ cut here ]------------ [ 915.196104] WARNING: CPU: 0 PID: 439 at /build/linux-R0TiM8/linux-4.4.0/net/wireless/sme.c:850 cfg80211_roamed+0x86/0xa0 [cfg80211]() [ 915.196106] Modules linked in: rfcomm bnep btusb btrtl btbcm btintel bluetooth binfmt_misc nls_iso8859_1 wl(POE) snd_hda_codec_hdmi snd_hda_codec_cirrus snd_hda_codec_generic snd_hda_intel snd_hda_codec uvcvideo snd_hda_core intel_rapl videobuf2_vmalloc videobuf2_memops x86_pkg_temp_thermal intel_powerclamp videobuf2_v4l2 videobuf2_core coretemp v4l2_common snd_hwdep kvm_intel snd_pcm videodev snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq media snd_seq_device snd_timer dell_wmi mei_me sparse_keymap kvm cfg80211 snd mei dell_laptop irqbypass crct10dif_pclmul dcdbas dell_smm_hwmon input_leds crc32_pclmul shpchp serio_raw soundcore cryptd mac_hid lpc_ich parport_pc ppdev lp parport autofs4 ums_realtek uas usb_storage i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect ahci sysimgblt fb_sys_fops [ 915.196155] libahci drm psmouse r8169 mii wmi video fjes [ 915.196163] CPU: 0 PID: 439 Comm: wl_event_handle Tainted: P W OE 4.4.0-38-generic #57-Ubuntu [ 915.196165] Hardware name: Dell Inc. Vostro 2520/0V1NDP, BIOS A11 02/24/2014 [ 915.196167] 0000000000000286 00000000ff0b74b0 ffff8800d5f4fdc8 ffffffff813f1b73 [ 915.196171] 0000000000000000 ffffffffc0375bd0 ffff8800d5f4fe00 ffffffff810811c2 [ 915.196173] ffff8800ce8d7000 ffff8800d7784840 0000000000000099 ffff8800d7784c00 [ 915.196177] Call Trace: [ 915.196184] [] dump_stack+0x63/0x90 [ 915.196189] [] warn_slowpath_common+0x82/0xc0 [ 915.196192] [] warn_slowpath_null+0x1a/0x20 [ 915.196210] [] cfg80211_roamed+0x86/0xa0 [cfg80211] [ 915.196260] [] wl_notify_roaming_status+0xc5/0x140 [wl] [ 915.196303] [] wl_event_handler+0x60/0x1d0 [wl] [ 915.196346] [] ? wl_notify_scan_status+0x320/0x320 [wl] [ 915.196349] [] kthread+0xd8/0xf0 [ 915.196352] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 915.196356] [] ret_from_fork+0x3f/0x70 [ 915.196358] [] ? kthread_create_on_node+0x1e0/0x1e0 [ 915.196360] ---[ end trace 91e2975807f31656 ]--- i'm attaching link to my wifi chipset information and additional information https://drive.google.com/file/d/0B1yBjoUMK1kMSlozeXVJdXlPb1U/view i have not yet applied the patch because i wanted to confirm the problem first. here is the link to my bug. https://answers.launchpad.net/ubuntu/+question/295795 i'm facing these problem from past two months(workaround usb tethering to access internet)