Managed to get the wifi stable by disabling n and power savings. sudo vi /etc/modprobe.d/iwlwifi-disable11n.conf Add this line: options iwlwifi 11n_disable=1 powertop to set Wireless Power Saving for interface wlan0 off
uname -a Linux p55t 3.13.0-20-generic #42-Ubuntu SMP Fri Mar 28 09:56:33 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux Some info from lspci (after the above config changes): 02:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73) Subsystem: Intel Corporation Wireless-N 7260 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 59 Region 0: Memory at f7d00000 (64-bit, non-prefetchable) [size=8K] Capabilities: [c8] Power Management version 3 Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee0800c Data: 41b1 Capabilities: [40] Express (v2) 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+ FLReset- 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, Exit Latency L0s <4us, L1 <32us ClockPM+ Surprise- LLActRep- BwNot- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Range B, TimeoutDis+, LTR+, OBFF Via WAKE# DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1- EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest- Capabilities: [100 v1] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, GenCap- CGenEn- ChkCap- ChkEn- Capabilities: [140 v1] Device Serial Number fc-f8-ae-ff-ff-58-32-b1 Capabilities: [14c v1] Latency Tolerance Reporting Max snoop latency: 3145728ns Max no snoop latency: 3145728ns Capabilities: [154 v1] Vendor Specific Information: ID=cafe Rev=1 Len=014 <?> Kernel driver in use: iwlwifi -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1289961 Title: Power management causes Intel wifi 7260 slowness Status in “linux” package in Ubuntu: Confirmed Bug description: I get a new ThinkPad T440s with Intel 7260 ac wireless. The dowload speed reachs an upper limit 400 kB/s instead of the normal 1500 kB/s I get with some other PC connected to my network. The speed often slows down very very low, especially when I'm far away from my AP. I use Ubuntu Trusty (Gnome) up-to-date. Removing N mode does not solve the issue. So I tried removing the wireless interface's power management in Powertop and it did solve the slowness issue. (iwconfig shows "Power management : off" in this case, obviously.) lspci************************ 03:00.0 Network controller: Intel Corporation Wireless 7260 (rev 83) lshw************************* *-network description: Interface réseau sans fil produit: Wireless 7260 fabriquant: Intel Corporation identifiant matériel: 0 information bus: pci@0000:03:00.0 nom logique: wlan0 version: 83 numéro de série: xxxxxxxxxxx bits: 64 bits horloge: 33MHz fonctionnalités: bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.13.0-16-generic firmware=22.24.8.0 ip=192.168.1.21 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn ressources: irq:61 mémoire:f0400000-f0401fff iwconfig******************************* wlan0 IEEE 802.11abgn ESSID:"Livebox" Mode:Managed Frequency:2.437 GHz Access Point: xxx Bit Rate=130 Mb/s Tx-Power=16 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on Link Quality=60/70 Signal level=-50 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:2549 Invalid misc:273 Missed beacon:0 ifconfig****************************** wlan0 Link encap:Ethernet HWaddr xxx inet adr:192.168.1.21 Bcast:192.168.1.255 Masque:255.255.255.0 adr inet6:xxx/64 Scope:Lien UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Packets reçus:30450 erreurs:0 :0 overruns:0 frame:0 TX packets:18296 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 lg file transmission:1000 Octets reçus:41761779 (41.7 MB) Octets transmis:1992389 (1.9 MB) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1289961/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp