Hello, My computer is Lenovo Thinkpad T400, and my operating system: Ubuntu Lucid (10.04), fully updated, kernel version: 2.6.32-23-generic lspci output: 00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 07) 00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:03.0 Communication controller: Intel Corporation Mobile 4 Series Chipset MEI Controller (rev 07) 00:03.3 Serial controller: Intel Corporation Mobile 4 Series Chipset AMT SOL Redirection (rev 07) 00:19.0 Ethernet controller: Intel Corporation 82567LM Gigabit Network Connection (rev 03) 00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) 00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) 00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) 00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) 00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03) 00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 4 (rev 03) 00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 03) 00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) 00:1f.0 ISA bridge: Intel Corporation ICH9M-E LPC Interface Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation ICH9M/M-E SATA AHCI Controller (rev 03) 00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03) 03:00.0 Network controller: Intel Corporation Wireless WiFi Link 5300 15:00.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ba) 15:00.1 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 04) And dmesg output: [ 307.427389] iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27k [ 307.427392] iwlagn: Copyright(c) 2003-2009 Intel Corporation [ 307.427493] iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [ 307.427527] iwlagn 0000:03:00.0: setting latency timer to 64 [ 307.428240] iwlagn 0000:03:00.0: Detected Intel Wireless WiFi Link 5300AGN REV=0x24 [ 307.465622] iwlagn 0000:03:00.0: Tunable channels: 13 802.11bg, 24 802.11a channels [ 307.465700] iwlagn 0000:03:00.0: irq 31 for MSI/MSI-X [ 307.466799] phy2: Selected rate control algorithm 'iwl-agn-rs' [ 307.472681] iwlagn 0000:03:00.0: firmware: requesting iwlwifi-5000-2.ucode [ 307.475391] iwlagn 0000:03:00.0: loaded firmware version 8.24.2.12 [ 307.665847] Registered led device: iwl-phy2::radio [ 307.666317] Registered led device: iwl-phy2::assoc [ 307.667259] Registered led device: iwl-phy2::RX [ 307.667325] Registered led device: iwl-phy2::TX [ 307.703063] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 307.703078] bridge-wlan0: enabling the bridge on dev up [ 307.703086] bridge-wlan0: is a Wireless Adapter [ 307.703097] bridge-wlan0: up [ 339.503983] wlan0: deauthenticating from 00:23:cd:19:10:d2 by local choice (reason=3) [ 339.504215] wlan0: direct probe to AP 00:23:cd:19:10:d2 (try 1) [ 339.509214] wlan0: direct probe responded [ 339.509223] wlan0: authenticate with AP 00:23:cd:19:10:d2 (try 1) [ 339.511554] wlan0: authenticated [ 339.511598] wlan0: associate with AP 00:23:cd:19:10:d2 (try 1) [ 339.515534] wlan0: RX AssocResp from 00:23:cd:19:10:d2 (capab=0x431 status=0 aid=1) [ 339.515542] wlan0: associated [ 339.528708] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready [ 343.178957] bridge-wlan0: disabling the bridge [ 343.220067] bridge-wlan0: down [ 343.220074] bridge-wlan0: detached [ 343.220117] /dev/vmnet: open called by PID 1290 (vmnet-bridge) [ 343.220127] /dev/vmnet: hub 0 does not exist, allocating memory. [ 343.220143] /dev/vmnet: port on hub 0 successfully opened [ 343.220151] bridge-wlan0: is a Wireless Adapter [ 343.220155] bridge-wlan0: up [ 343.220159] bridge-wlan0: attached [ 350.170033] wlan0: no IPv6 routers present [ 351.958154] iwlagn 0000:03:00.0: Microcode SW error detected. Restarting 0x2000000. [ 351.997290] Registered led device: iwl-phy2::radio [ 351.997461] Registered led device: iwl-phy2::assoc [ 351.997704] Registered led device: iwl-phy2::RX [ 351.998097] Registered led device: iwl-phy2::TX [ 357.979594] iwlagn 0000:03:00.0: iwl_tx_agg_start on ra = 00:23:cd:19:10:d2 tid = 0 [ 379.545540] iwlagn 0000:03:00.0: Microcode SW error detected. Restarting 0x2000000. [ 379.587374] Registered led device: iwl-phy2::radio [ 379.587542] Registered led device: iwl-phy2::assoc [ 379.587762] Registered led device: iwl-phy2::RX [ 379.588152] Registered led device: iwl-phy2::TX [ 379.602455] iwlagn 0000:03:00.0: Stopping AGG while state not ON or starting [ 379.602466] iwlagn 0000:03:00.0: queue number out of range: 0, must be 10 to 19 [ 379.602473] ------------[ cut here ]------------ [ 379.602516] WARNING: at /build/buildd/linux-2.6.32/net/mac80211/agg-tx.c:150 ___ieee80211_stop_tx_ba_session+0x82/0x90 [mac80211]() [ 379.602522] Hardware name: 6474DU8 [ 379.602526] Modules linked in: iwlagn cryptd aes_x86_64 aes_generic hidp hid rfcomm binfmt_misc sco bridge stp bnep l2cap hdaps vmnet ppdev parport_pc vmblock vsock vmci vmmon joydev psmouse serio_raw snd_hda_codec_conexant fbcon tileblit font bitblit softcursor vga16fb vgastate btusb bluetooth arc4 pcmcia coretemp snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss thinkpad_acpi tp_smapi snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq thinkpad_ec snd_timer snd_seq_device yenta_socket iwlcore snd rsrc_nonstatic mac80211 i915 drm_kms_helper led_class nvram tpm_tis tpm tpm_bios pcmcia_core soundcore snd_page_alloc cfg80211 intel_agp drm i2c_algo_bit video output lp parport ohci1394 ieee1394 e1000e ahci [last unloaded: iwlagn] [ 379.602661] Pid: 9, comm: events/0 Tainted: G W 2.6.32-23-generic #37-Ubuntu [ 379.602666] Call Trace: [ 379.602684] [] warn_slowpath_common+0x7b/0xc0 [ 379.602692] [] warn_slowpath_null+0x14/0x20 [ 379.602714] [] ___ieee80211_stop_tx_ba_session+0x82/0x90 [mac80211] [ 379.602738] [] __ieee80211_stop_tx_ba_session+0x7f/0x90 [mac80211] [ 379.602761] [] ieee80211_sta_tear_down_BA_sessions+0x27/0x50 [mac80211] [ 379.602789] [] ieee80211_reconfig+0x378/0x460 [mac80211] [ 379.602810] [] ? ieee80211_restart_work+0x0/0x30 [mac80211] [ 379.602831] [] ieee80211_restart_work+0x22/0x30 [mac80211] [ 379.602842] [] run_workqueue+0xc7/0x1a0 [ 379.602850] [] worker_thread+0xa3/0x110 [ 379.602859] [] ? autoremove_wake_function+0x0/0x40 [ 379.602868] [] ? worker_thread+0x0/0x110 [ 379.602875] [] kthread+0x96/0xa0 [ 379.602884] [] child_rip+0xa/0x20 [ 379.602891] [] ? kthread+0x0/0xa0 [ 379.602898] [] ? child_rip+0x0/0x20 [ 379.602904] ---[ end trace 13b28fcec451d00c ]--- My router is 802.11n compatible. probably workarond: rmmod iwlagn modprobe iwlagn 11n_disable50=1