WiFi connection suddenly drops

[Detlev Zundel]

This started to happen only with newer kernel versions. The WiFi was previously absolutely solid. When the WiFi connection drops, there are clear kernel error messages:

Apr 08 22:39:29 konstantin kernel: iwl3945 0000:02:00.0: Queue 4 stuck for 2048 ms.
Apr 08 22:39:30 konstantin kernel: iwl3945 0000:02:00.0: On demand firmware reload
Apr 08 22:39:30 konstantin kernel: ieee80211 phy0: Hardware restart was requested
Apr 08 22:39:30 konstantin kernel: iwl3945 0000:02:00.0: BSM uCode verification failed at addr 0x00003800+0
Apr 08 22:39:30 konstantin kernel: iwl3945 0000:02:00.0: Unable to set up bootstrap uCode: -5

The last two messsages are repeated a few times. This is followed by more detailed stack traces, but the hardware does not recover. Unloading the iwl3945 module and reloading it did not help in a few tests.

Looking at the log some more, I see this line

Apr 08 22:33:38 konstantin kernel: iwl3945 0000:02:00.0: Enabling power save might cause firmware crashes

I will try to find out if this can be disabled and do more test then.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-image-4.13.0-37-generic 4.13.0-37.42
ProcVersionSignature: Ubuntu 4.13.0-37.42-generic 4.13.13
Uname: Linux 4.13.0-37-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: regina 1098 F.... pulseaudio
CurrentDesktop: GNOME
Date: Sun Apr 8 22:56:35 2018
HibernationDevice: RESUME=UUID=4c990619-fde4-4d44-b45a-f240be602537
InstallationDate: Installed on 2017-04-19 (354 days ago)
InstallationMedia: Ubuntu-GNOME 17.04 "Zesty Zapus" - Release amd64 (20170412)
MachineType: Hewlett-Packard HP Pavilion dv6500 Notebook PC
ProcEnviron:
 LANG=de_DE.UTF-8
 TERM=xterm-256color
 SHELL=/bin/bash
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, no user)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-37-generic root=/dev/mapper/ubuntu--gnome--vg-root ro quiet splash video=SVIDEO-1:d vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-37-generic N/A
 linux-backports-modules-4.13.0-37-generic N/A
 linux-firmware 1.169.3
SourcePackage: linux
UpgradeStatus: Upgraded to artful on 2018-01-19 (78 days ago)
dmi.bios.date: 04/04/2007
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.05
dmi.board.name: 30CC
dmi.board.vendor: Quanta
dmi.board.version: 79.10
dmi.chassis.type: 10
dmi.chassis.vendor: Quanta
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.05:bd04/04/2007:svnHewlett-Packard:pnHPPaviliondv6500NotebookPC:pvrRev1:rvnQuanta:rn30CC:rvr79.10:cvnQuanta:ct10:cvrN/A:
dmi.product.family: 103C_5335KV
dmi.product.name: HP Pavilion dv6500 Notebook PC
dmi.product.version: Rev 1
dmi.sys.vendor: Hewlett-Packard

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[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 v4.16 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/v4.16

[Launchpad Janitor (janitor)]

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

[Christian Weisel (christian-weisel)]

Same issue here with a Lenovo Thinkpad T61 with 18.04 (standard kernel).
Seems to be that iwl3945 has an issue with having the driver feature "power save" activated.

This might be related to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1627828

What works for me thins some weeks without any issue is the following:

Type iwconfig and look at the output. You should see the name of your chip-set as well as the whether power management is off or on. If it doesn't say, it is probably off.
To turn off power management, go to /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf and you will see

[connection]
wifi.powersave = 3

For reference: https://gist.github.com/jcberthon/ea8cfe278998968ba7c5a95344bc8b55

Would it be possible to change the WiFi setup process in system installer to disable power save for iwl3945.

Other option: Ignore power save setting for iwl3945 in kernel driver?
Just some ideas.

[Joe E Clark (joeclarkia)]

Just experienced this bug on Xubuntu 20.04.1.

[Thorsten Munsch (thorsten-munsch)]

I ran into this issue in Xubuntu 20.04 (5.4 and 5.8 kernel) aswell.

Changing wifi.powersave from default 3 to 0 (no override = off in my case) solves it.

Thanks for the info, @Christian.