Attempting to follow http://wireless.kernel.org/en/users/Documentation/iw#Setting_TX_power I get: sudo iw dev wlan1 set txpower fixed 14 command failed: Invalid argument (-22) Same error if I raise or lower this number. My environment: + Ubuntu 14.10 (also reproducible in 14.04) + (Also reproducible in 3.13.x) uname -a Linux acer-pc 3.16.0-29-generic #39-Ubuntu SMP Mon Dec 15 22:27:29 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux + I am in the US regulatory domain. + wlan1 usb-devices T: Bus=02 Lev=02 Prnt=02 Port=01 Cnt=01 Dev#= 3 Spd=480 MxCh= 0 D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 P: Vendor=050d ProdID=845a Rev=02.00 S: Manufacturer=Manufacturer Realtek S: Product=Belkin USB Wireless Adaptor S: SerialNumber=00e04c000001 C: #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=500mA I: If#= 0 Alt= 0 #EPs= 4 Cls=ff(vend.) Sub=ff Prot=ff Driver=r8712u + wlan0 lspci -vvnn 03:00.0 Network controller [0280]: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) [168c:002e] (rev 01) Subsystem: Foxconn International, Inc. Device [105b:e034] 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 17 Region 0: Memory at c0500000 (64-bit, non-prefetchable) [size=64K] Capabilities: <access denied> Kernel driver in use: ath9k + I don't have network-manager or wicd installed. I've configured both wlan0 and wlan1 in /etc/network/interfaces : # interfaces(5) file used by ifup(8) and ifdown(8) auto lo wlan0 wlan1 iface lo inet loopback # wlan0 access point iface wlan0 inet static address 10.0.0.1 netmask 255.255.255.240 gateway 10.0.0.1 wireless-mode Master # wlan1 managed mode iface wlan1 inet static address 192.168.1.10 network 192.168.1.0 netmask 255.255.255.0 gateway 192.168.1.1 wpa-bssid XX:XX:XX:XX:XX:XX wpa-ssid SSID wpa-psk PASSWORD + Strangely, the following does not show a phy0 and a phy1, but both wlan0 and wlan1 work fine: iw list Wiphy phy0 max # scan SSIDs: 4 max scan IEs length: 2257 bytes Coverage class: 0 (up to 0m) Device supports RSN-IBSS. Device supports AP-side u-APSD. Device supports T-DLS. Supported Ciphers: * WEP40 (00-0f-ac:1) * WEP104 (00-0f-ac:5) * TKIP (00-0f-ac:2) * CCMP (00-0f-ac:4) * CMAC (00-0f-ac:6) Available Antennas: TX 0x3 RX 0x3 Configured Antennas: TX 0x3 RX 0x3 Supported interface modes: * IBSS * managed * AP * AP/VLAN * WDS * monitor * mesh point * P2P-client * P2P-GO Band 1: Capabilities: 0x11ee HT20/HT40 SM Power Save disabled RX HT20 SGI RX HT40 SGI TX STBC RX STBC 1-stream Max AMSDU length: 3839 bytes DSSS/CCK HT40 Maximum RX AMPDU length 65535 bytes (exponent: 0x003) Minimum RX AMPDU time spacing: 8 usec (0x06) HT TX/RX MCS rate indexes supported: 0-15 Bitrates (non-HT): * 1.0 Mbps * 2.0 Mbps (short preamble supported) * 5.5 Mbps (short preamble supported) * 11.0 Mbps (short preamble supported) * 6.0 Mbps * 9.0 Mbps * 12.0 Mbps * 18.0 Mbps * 24.0 Mbps * 36.0 Mbps * 48.0 Mbps * 54.0 Mbps Frequencies: * 2412 MHz [1] (16.0 dBm) * 2417 MHz [2] (16.0 dBm) * 2422 MHz [3] (16.0 dBm) * 2427 MHz [4] (16.0 dBm) * 2432 MHz [5] (16.0 dBm) * 2437 MHz [6] (16.0 dBm) * 2442 MHz [7] (16.0 dBm) * 2447 MHz [8] (16.0 dBm) * 2452 MHz [9] (16.0 dBm) * 2457 MHz [10] (16.0 dBm) * 2462 MHz [11] (16.0 dBm) * 2467 MHz [12] (disabled) * 2472 MHz [13] (disabled) * 2484 MHz [14] (disabled) Supported commands: * new_interface * set_interface * new_key * start_ap * new_station * new_mpath * set_mesh_config * set_bss * authenticate * associate * deauthenticate * disassociate * join_ibss * join_mesh * remain_on_channel * set_tx_bitrate_mask * frame * frame_wait_cancel * set_wiphy_netns * set_channel * set_wds_peer * tdls_mgmt * tdls_oper * probe_client * set_noack_map * register_beacons * start_p2p_device * set_mcast_rate * Unknown command (104) * connect * disconnect Supported TX frame types: * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * mesh point: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 * P2P-device: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0 Supported RX frame types: * IBSS: 0x40 0xb0 0xc0 0xd0 * managed: 0x40 0xd0 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0 * mesh point: 0xb0 0xc0 0xd0 * P2P-client: 0x40 0xd0 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0 * P2P-device: 0x40 0xd0 software interface modes (can always be added): * AP/VLAN * monitor valid interface combinations: * #{ managed } <= 2048, #{ AP, mesh point } <= 8, #{ P2P-client, P2P-GO } <= 1, total <= 2048, #channels <= 1, STA/AP BI must match * #{ WDS } <= 2048, total <= 2048, #channels <= 1, STA/AP BI must match HT Capability overrides: * MCS: ff ff ff ff ff ff ff ff ff ff * maximum A-MSDU length * supported channel width * short GI for 40 MHz * max A-MPDU length exponent * min MPDU start spacing Device supports TX status socket option. Device supports HT-IBSS. Device supports low priority scan. Device supports scan flush. Device supports AP scan. When I run wavemon -i wlan1 it does not show a tx-power. However, if I run wavemon on a different computer with the following chipset, it does show tx-power: lspci -vvnn 02:00.0 Network controller [0280]: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter [168c:0036] (rev 01) Subsystem: Lenovo Device [17aa:3026] 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 36 Region 0: Memory at f0800000 (64-bit, non-prefetchable) [size=512K] Expansion ROM at f0880000 [disabled] [size=64K] Capabilities: <access denied> Kernel driver in use: ath9k However, this chipset also cannot have the txpower changed for a different reason: sudo iw dev wlan0 set txpower fixed 14 command failed: Operation not supported (-95) I've spent the better part of this weekend looking through countless forums, mailing lists, man pages, etc. and have not been provided a clear answer to any of this. Anything you could do to clear this up is greatly appreciated. Thank you for your time and consideration in this matter. Christopher M. Penalver E-Mail: christopher.m.penalver@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html