Comment 21 for bug 642901

Same here on a new install of 11.04, kernel 2.6.38-10. The same effect appears with two different wireless cards (one is onboard). They use the same kernel module: ath5k.. The extension card has no hardware on/off switch.

iwconfig:
wlan0 IEEE 802.11bg ESSID:off/any
          Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
          Tx-Power=20 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off

wlan1 IEEE 802.11bg ESSID:off/any
          Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
          Tx-Power=20 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off

lspci:
06:02.0 Ethernet controller: Atheros Communications Inc. AR2413 802.11bg NIC (rev 01)
 Subsystem: AMBIT Microsystem Corp. Device 0418
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 168 (2500ns min, 7000ns max), Cache Line Size: 32 bytes
 Interrupt: pin A routed to IRQ 22
 Region 0: Memory at fc110000 (32-bit, non-prefetchable) [size=64K]
 Capabilities: [44] Power Management version 2
  Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=2 PME-
 Kernel driver in use: ath5k
 Kernel modules: ath5k

--
07:00.0 Ethernet controller: Atheros Communications Inc. Atheros AR5001X+ Wireless Network Adapter (rev 01)
 Subsystem: Device 02fa:3070
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 168 (2500ns min, 7000ns max), Cache Line Size: 32 bytes
 Interrupt: pin A routed to IRQ 20
 Region 0: Memory at 28000000 (32-bit, non-prefetchable) [size=64K]
 Capabilities: [44] Power Management version 2
  Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=2 PME-
 Kernel driver in use: ath5k
 Kernel modules: ath5k