Wifi drops out regularly after upgrade to 16.04

[Shaun Crampton]

Since upgrading to 16.04, my wifi has seemed a lot more flaky, it'll drop out for 20s every few minutes then come back. network manager still thinks that it is connected, but websites will fail to load/time out. Reconnecting to the AP (by clicking on it in network-manager) seems to re-establish the connection. I typically sit 6ft from the access point so the signal is strong and much stronger than any nearby APs.

WORKAROUND: Disable 40MHz bands on my router.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-45-generic 4.4.0-45.66
ProcVersionSignature: Ubuntu 4.4.0-45.66-generic 4.4.21
Uname: Linux 4.4.0-45-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: shaun 2212 F.... pulseaudio
CurrentDesktop: Unity
Date: Sat Nov 19 10:39:23 2016
HibernationDevice: RESUME=UUID=e9e7a3d6-2d7f-4d2d-8880-ace10b4a942f
InstallationDate: Installed on 2012-09-26 (1515 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120905.2)
MachineType: SAMSUNG ELECTRONICS CO., LTD. 900X3C/900X3D/900X4C/900X4D
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-45-generic root=/dev/mapper/ubuntu-root ro quiet splash intel_pstate=enable vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-45-generic N/A
 linux-backports-modules-4.4.0-45-generic N/A
 linux-firmware 1.157.4
SourcePackage: linux
UpgradeStatus: Upgraded to xenial on 2016-04-25 (207 days ago)
dmi.bios.date: 07/12/2012
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: P03AAC
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: SAMSUNG_NP1234567890
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: FAB1
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvrP03AAC:bd07/12/2012:svnSAMSUNGELECTRONICSCO.,LTD.:pn900X3C/900X3D/900X4C/900X4D:pvr0.1:rvnSAMSUNGELECTRONICSCO.,LTD.:rnSAMSUNG_NP1234567890:rvrFAB1:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvr0.1:
dmi.product.name: 900X3C/900X3D/900X4C/900X4D
dmi.product.version: 0.1
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Jeremy (wa113y3s)]

See if the following in terminal helps

sudo sed -i 's/wifi.powersave = 3/wifi.powersave = 2/' /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

systemctl restart network-manager

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.9 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9-rc6

[Shaun Crampton (fasaxc)]

Running 4.9.0-040900rc6, just had a drop out. Noticed that dmesg had this output:

First this line, which seemed to coincide with the dropout:

[ 3627.072802] wlan0: AP 00:07:26:aa:e0:45 changed bandwidth, new config is 2462 MHz, width 2 (2452/0 MHz)

Then, after a minute, this and it came back:

[ 3707.386740] wlan0: authenticate with 00:07:26:aa:e0:45
[ 3707.394906] wlan0: send auth to 00:07:26:aa:e0:45 (try 1/3)
[ 3707.397243] wlan0: authenticated
[ 3707.397828] wlan0: associate with 00:07:26:aa:e0:45 (try 1/3)
[ 3707.406078] wlan0: RX AssocResp from 00:07:26:aa:e0:45 (capab=0x431 status=0 aid=1)
[ 3707.413670] wlan0: associated
[ 3707.447412] wlan0: Limiting TX power to 20 (20 - 0) dBm as advertised by 00:07:26:aa:e0:45

[penalvch (penalvch)]

Shaun Crampton, to clarify:
1) What Ubuntu release did you upgrade from where this issue didn't occur?
2) Could you please provide the full computer model as noted on the sticker of the computer itself (not from the Bug Description, or the result of a terminal command)?
3) Could you please provide the full router model and manufacturer as per the sticker?

[Shaun Crampton (fasaxc)]

Ah, after disabling 40MHz bands on my router, the problem seems to have gone away; seems the bug is triggered by the router switching between 20 and 40MHz.

[Launchpad Janitor (janitor)]

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