8086:08b1 [Dell Latitude E7440] WiFi issue

[Thomas Vachon]

Using the Intel 7260 AC Wireless chipset, there is a noticeable slowdown and multiple disconnection problem. When connected to a hotspot it is unusable (multiple disconnections, ICMP times nearly 8000MS). It does appear to be the chipset specifically, because USB tethering or being wired via ethernet do not exhibit this problem, it is only using the WiFi chip.

Intel Corporation Wireless 7260 [8086:08b1] (rev 73)
Subsystem: Intel Corporation Dual Band Wireless-AC 7260 [8086:4470]

WORKAROUND: Turn off power management via:
iwconfig wlan0 power off

or blacklisting via:
echo 'HOOK_BLACKLIST="wireless"' > /etc/pm.d/config.d/blacklist

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-24-generic 3.13.0-24.47
ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: vachon 31131 F.... pulseaudio
 /dev/snd/controlC0: vachon 31131 F.... pulseaudio
CurrentDesktop: GNOME
Date: Thu May 15 07:39:15 2014
HibernationDevice: RESUME=UUID=63c1784a-b66a-498f-ac43-5fea2ee96bdc
InstallationDate: Installed on 2014-04-03 (41 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Beta amd64 (20140326)
MachineType: Dell Inc. Latitude E7440
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic root=UUID=54753b1d-b028-408f-a48d-71e020359a84 ro quiet splash vt.handoff=7
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
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog: May 15 07:36:03 vachon-dbp kernel: [203016.704005] wireshark[2344]: segfault at 7fffe7106ff8 ip 00007fc51ad8bad5 sp 00007fffe7106ff0 error 6 in libc-2.19.so[7fc51ad0b000+1bc000]
dmi.bios.date: 02/18/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A08
dmi.board.name: 091TRH
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA08:bd02/18/2014:svnDellInc.:pnLatitudeE7440:pvr01:rvnDellInc.:rn091TRH:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E7440
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Thomas Vachon (vachon)]

Using the Intel 7260 AC Wireless chipset, there is a noticeable slowdown and multiple disconnection problem. When connected to a hotspot it is unusable (multiple disconnections, ICMP times nearly 8000MS). Turning off power management via "iwconfig wlan0 power off" seems to resolve the issue.

When the power management is on, you see excessive retries and also spectrum hopping (2.4 to 5.0 and back). The reported link quality is reported by iwconfig between 15-25 out of 70 even though the source is within inches or up to 3 feet away.

When connected to a 802.1b/g/n/a/ac infrastructure network, you will seep speeds around 2Mbit, and quick dropping to 100-300Kbit on download (testing via large file gets and HTML5 speed testing).

Turning power management off and blacklisting via echo 'HOOK_BLACKLIST="wireless"' > /etc/pm.d/config.d/blacklist seems to resoove the issue. The exessive retries do not exist nor does the spectrum hopping. The provisioned speeds in both highly interfere WiFi areas and interfere-less areas match the expected speeds 50-80Mbit Download / 8-15Mbit Upload. Testing via a local large file, similarly does not have the same issue.

It does appear to be the chipset specifically, because USB tethering or being wired via ethernet do not exhibit this problem, it is only using the WiFi chip.

[penalvch (penalvch)]

Thomas Vachon, could you please test the latest upstream kernel available (not the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-3.15-rc5

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Thomas Vachon (vachon)]

The upstream mainline (3.15.0-031500rc2-generic #201404201435) has seemed to make a difference for the better. I will continue to monitor.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Ahmet Yıldırım (regenx)]

ApportVersion: 2.14.1-0ubuntu3.3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: ahmety 2393 F.... pulseaudio
 /dev/snd/controlC0: ahmety 2393 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=2bf1b1f3-09e1-415d-a808-c5f2ba780f42
InstallationDate: Installed on 2014-08-04 (9 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: Hewlett-Packard HP EliteBook 8560w
NonfreeKernelModules: nvidia
Package: linux (not installed)
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-33-generic root=UUID=75376b80-2061-498d-958e-e59b2aa93906 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.13.0-33.58-generic 3.13.11.4
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-33-generic N/A
 linux-backports-modules-3.13.0-33-generic N/A
 linux-firmware 1.127.5
Tags: trusty
Uname: Linux 3.13.0-33-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm lpadmin sambashare sudo wireshark
_MarkForUpload: True
dmi.bios.date: 07/15/2013
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 68SVD Ver. F.42
dmi.board.name: 1631
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 01.3D
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr68SVDVer.F.42:bd07/15/2013:svnHewlett-Packard:pnHPEliteBook8560w:pvrA0001D02:rvnHewlett-Packard:rn1631:rvrKBCVersion01.3D:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP EliteBook 8560w
dmi.product.version: A0001D02
dmi.sys.vendor: Hewlett-Packard

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[Ahmet Yıldırım (regenx)]

apport information

[penalvch (penalvch)]

ahmet yildirim, thank you for your comment. Unfortunately, this bug report is not scoped to you, or your problem. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into the default Ubuntu kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

As well, please do not announce in this report you created a new bug report.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs