Same Problem with Intel Corporation PRO/Wireless 3945ABG.  (I have no problems in Karmic)

"Ubuntu does not report that the connection has dropped.  Instead, it re-associates in the background"


Ubuntu Lucid 10.04
2.6.32-21-generic
Network-Manager


test@lucid:~/Desktop$ lspci -nnvv

0c:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection [8086:4222] (rev 02)
	Subsystem: Intel Corporation Device [8086:1020]
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 28
	Region 0: Memory at f9fff000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: [c8] Power Management version 2
		Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
		Status: D0 PME-Enable- DSel=0 DScale=0 PME-
	Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable+
		Address: 00000000fee0300c  Data: 41a9
	Capabilities: [e0] Express (v1) Legacy Endpoint, MSI 00
		DevCap:	MaxPayload 128 bytes, PhantFunc 0, Latency L0s <512ns, L1 unlimited
			ExtTag- AttnBtn- AttnInd- PwrInd- RBE- FLReset-
		DevCtl:	Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
			RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
			MaxPayload 128 bytes, MaxReadReq 128 bytes
		DevSta:	CorrErr+ UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend-
		LnkCap:	Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 <128ns, L1 <64us
			ClockPM+ Suprise- LLActRep- BwNot-
		LnkCtl:	ASPM L1 Enabled; RCB 64 bytes Disabled- Retrain- CommClk+
			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
		LnkSta:	Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
	Capabilities: [100] Advanced Error Reporting <?>
	Capabilities: [140] Device Serial Number 23-0c-81-ff-ff-bf-1c-00
	Kernel driver in use: iwl3945
	Kernel modules: iwl3945


test@lucid:~$ dmesg | grep iwl3945

[  620.633131] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26ks
[  620.633137] iwl3945: Copyright(c) 2003-2009 Intel Corporation
[  620.633245] iwl3945 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[  620.633266] iwl3945 0000:0c:00.0: setting latency timer to 64
[  620.690117] iwl3945 0000:0c:00.0: Tunable channels: 11 802.11bg, 13 802.11a channels
[  620.690122] iwl3945 0000:0c:00.0: Detected Intel Wireless WiFi Link 3945ABG
[  620.690275] iwl3945 0000:0c:00.0: irq 28 for MSI/MSI-X
[  620.702708] iwl3945 0000:0c:00.0: firmware: requesting iwlwifi-3945-2.ucode
[  620.726686] iwl3945 0000:0c:00.0: loaded firmware version 15.32.2.9


test@lucid:~$ dmesg

[ 4887.102556] No probe response from AP 00:25:9c:41:67:1e after 500ms, disconnecting.
[ 4889.147057] wlan0: direct probe to AP 00:25:9c:41:67:1e (try 1)
[ 4889.149184] wlan0: direct probe responded
[ 4889.149192] wlan0: authenticate with AP 00:25:9c:41:67:1e (try 1)
[ 4889.151104] wlan0: authenticated
[ 4889.151240] wlan0: associate with AP 00:25:9c:41:67:1e (try 1)
[ 4889.154040] wlan0: RX AssocResp from 00:25:9c:41:67:1e (capab=0x431 status=0 aid=1)
[ 4889.154046] wlan0: associated


test@lucid:~/Desktop$ iw event -t

1272824302.007927: wlan0 (phy #1): scan started
1272824305.422091: wlan0 (phy #1): scan finished: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 5180 5200 5220 5240 5260 5280 5300 5320 5745 5765 5785 5805 5825, ""
1272824307.967365: wlan0 (phy #1): deauth 00:1c:bf:81:0c:23 -> 00:25:9c:41:67:1e reason 4: Disassociated due to inactivity
1272824307.967507: wlan0 (phy #1): disconnected (local request)
1272824308.098970: wlan0 (phy #1): scan started
1272824309.920060: wlan0 (phy #1): scan finished: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 5180 5200 5220 5240 5260 5280 5300 5320 5745 5765 5785 5805 5825, "sam+"
1272824309.926388: wlan0 (phy #1): auth 00:25:9c:41:67:1e -> 00:1c:bf:81:0c:23 status: 0: Successful
1272824309.932772: wlan0 (phy #1): assoc 00:25:9c:41:67:1e -> 00:1c:bf:81:0c:23 status: 0: Successful
1272824309.932847: wlan0 (phy #1): connected to 00:25:9c:41:67:1e


Similar bugs...

Lucid - iwl3945 drops connection on youtube but not with mainline
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/564376

[Karmic] Intel Pro/Wireless 3945BG (driver: iwl3945) disconnects frequently at random
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/429035