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Since I updated my Acer 1810TZ laptop to 16.04 WIFI is unstable.

Intel Centrino Wireless-N 1000.

dmesg | grep iwlwifi
[    4.897866] iwlwifi 0000:02:00.0: can't disable ASPM; OS doesn't have ASPM control
[    4.904631] iwlwifi 0000:02:00.0: loaded firmware version 39.31.5.1 build 35138 op_mode iwldvm
[    4.960067] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUG disabled
[    4.960074] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUGFS enabled
[    4.960078] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[    4.960083] iwlwifi 0000:02:00.0: Detected Intel(R) Centrino(R) Wireless-N 1000 BGN, REV=0x6C
[    4.962373] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled

I had bad WIFI performance in the past but in 15.10 it was working perfectly.

I have this in the dmesg:

7639.025981] wlan0: deauthenticating from 64:66:b3:4f:eb:5d by local choice (Reason: 3=DEAUTH_LEAVING)
[ 7639.160055] cfg80211: World regulatory domain updated:
[ 7639.160062] cfg80211:  DFS Master region: unset

I read some tips to disable power settings sudo iwconfig wlan0 power off, but that doesn't make much difference now. Any ideas to improve it? Can I use different firmware or how to debug?

Janghou
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2 Answers2

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WIFI current regulatory domain

It seems my WIFI country code for the Kernels current regulatory domain wasn't set.

Update that and reboot:

sudo nano /etc/default/crda

REGDOMAIN=UK

New upstream kernel

Probably more important, I also tried a new upstream kernel

I saw WIFI bug-reports that were fixed with a new kernel. Read more about upstream kernels here.

Download and install the packages that corresponds to your architecture (e.g. AMD64, kernel 4.6-rc7-wily)

linux-headers-4.6.0-040600rc7-generic_4.6.0-040600rc7.201605081830_amd64.deb
linux-headers-4.6.0-040600rc7_4.6.0-040600rc7.201605081830_all.deb
linux-image-4.6.0-040600rc7-generic_4.6.0-040600rc7.201605081830_amd64.deb


sudo dpkg -i *.deb
sudo reboot

It seems to have solved my problem.

Janghou
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  • is it possible that the first option is more important? With kernel 4.15 I have the same problem. The explanatory link is dead now. –  Jul 13 '18 at 20:21
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    Fixed the link. I do not have the problem with 18.04 (new install). – Janghou Jul 14 '18 at 11:26
  • I had great hopes in the regdomain fix but it didn't work in 18.04. - Yours is the only post here that describes something close to what I am experiencing with this Centrino thing. Between 2-3 times a day and once every 2-3 days I have sudden disconnection, especially when downloading (and not only 18.04, in 16 too, also in Fedora, Solus etc). - Glad it works for you now. –  Jul 15 '18 at 11:37
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    It's a nasty problem. I remember the problem showed up and disappeared, caused by (kernel) updates IMHO. I can remember using workarounds like disabling WIFI N, disabling power save mode, or using an extra cheap USB WIFI adapter for some time. I'm not bothered by the problem lately. Did you do a upgrade or a new install for 18.04. Try a live image and see if the problem shows up. – Janghou Jul 15 '18 at 12:24
  • I have an updated system, and the problem appears quickly after fresh installs. I see no reason why a live session wouldn't be affected. Do you? –  Jul 16 '18 at 14:28
  • Well, things are worth trying. It's not your router? AFAICR my problem showed up several times an hour. I had to disable/enable wifi to get stable WIFI for 15 minutes. Do yo have the same hardware? Have you filed a bug report? – Janghou Jul 18 '18 at 16:48
  • I have the same Centrino hardware it seems. I'm not the man for bug reports sadly. Interruptions are relatively rare, I cannot say the connection is not stable. I cannot fully rule out some router issue, although Windows and Mac computers connected to the same wifi are not affected. The problem seems to me that disconnection is not immediately followed by re-connection in all systems. I have seen on some Mate desktop the wifi tool reconnecting immediately, by contrast to other cases. Also, testing Lxqt with Wicd tool, the latter always reconnects in a sec or two. –  Jul 19 '18 at 14:00
  • That sounds like a sick man refusing to go to a doctor. How do you expect things to get fixed without a proper bug-report? https://askubuntu.com/questions/5121/how-do-i-report-a-bug – Janghou Jul 20 '18 at 07:22
  • It feels more like I'm expected to play the doctor myself, be an enthusiastic member of the Linux community. :) While I'm a very skeptical one. The Intel driver is the culprit I think, but how can I be sure. –  Jul 20 '18 at 07:32
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I had a similar issue following an update a couple of day ago. With, arguably, a more ominous dmesg. ;)

However, I just checked updates, which there were (headers, etc), and I'm now completely back to normal (on Debian 9 stretch).

Best.

bezoris
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