I can confirm the problem, and also tried to update the kernel to 3.17.3 and use the latest driver 23.11.10.0, but the speed was still much lower than using the 22.24.8.0 so I reverted back. Hope it is resolved.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-firmware in Ubuntu. https://bugs.launchpad.net/bugs/1289961 Title: 8086:08b2 [Lenovo ThinkPad T440s] Power management causes Intel wifi 7260 slowness Status in linux-firmware package in Ubuntu: Triaged Bug description: With power management on, download speed reaches 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. Removing N mode does not solve the issue. 03:00.0 Network controller [0280]: Intel Corporation Wireless 7260 [8086:08b2] (rev 83) Subsystem: Intel Corporation Dual Band Wireless-AC 7260 [8086:c270] This is a regression in Trusty update going from linux-firmware 1.127 to 1.127.10. As per https://launchpad.net/ubuntu/+archive/primary/+files/linux-firmware_1.127.tar.gz this is how 1.127 only included: /linux-firmware/iwlwifi-7260-7.ucode /linux-firmware/iwlwifi-7260-8.ucode However, as per https://launchpad.net/ubuntu/+archive/primary/+files/linux-firmware_1.127.10.tar.gz it includes: /linux-firmware/iwlwifi-7260-8.ucode /linux-firmware/iwlwifi-7260-9.ucode WORKAROUND: Remove wireless interface's power management via Powertop or WORKAROUND: Revert to previous iwlwifi-7260-8.ucode (remove the -9 version from /lib/firmware) WORKAROUND: Use latest Intel upstream firmware iwlwifi-7260-ucode-23.10.10.0 with 3.17+ kernels WORKAROUND : use the default (25.222.9.0) firmware and disable uAPSD (see message #64) --- ApportVersion: 2.14.1-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: ft 1884 F.... pulseaudio /dev/snd/controlC0: ft 1884 F.... pulseaudio DistroRelease: Ubuntu 14.04 HibernationDevice: RESUME=UUID=54b265b9-4433-42d4-8d0f-fac028ee7030 InstallationDate: Installed on 2014-03-05 (46 days ago) InstallationMedia: Ubuntu-GNOME 14.04 "Trusty Tahr" - Alpha amd64 (20140226) Lsusb: Bus 001 Device 002: ID 8087:8000 Intel Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: LENOVO 20AQCTO1WW Package: linux (not installed) ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=fr_FR.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=b1cbc034-b66f-4f6c-9d61-507b8cb23ffe ro quiet ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-3.13.0-24-generic N/A linux-backports-modules-3.13.0-24-generic N/A linux-firmware 1.127 RfKill: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no Tags: trusty Uname: Linux 3.13.0-24-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True dmi.bios.date: 03/28/2014 dmi.bios.vendor: LENOVO dmi.bios.version: GJET75WW (2.25 ) dmi.board.asset.tag: Not Available dmi.board.name: 20AQCTO1WW dmi.board.vendor: LENOVO dmi.board.version: 0B98405 STD dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvrGJET75WW(2.25):bd03/28/2014:svnLENOVO:pn20AQCTO1WW:pvrThinkPadT440s:rvnLENOVO:rn20AQCTO1WW:rvr0B98405STD:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 20AQCTO1WW dmi.product.version: ThinkPad T440s dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+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