Ubuntu – Wireless automatic disconnected

kernelnetworkingwireless

04-22-2015

My internal wireless adapter become disabled (the wireless led indicator isn't lighted), when I mount my laptop on a laptop table from my desk. Restart Ubuntu is the only solution I know to make it work again.

The output of the script is here, with no wired connection, and no external usb wireless adapter plugged in and with no driver modules loaded.

The output of lshw is here, with the external usb wireless adapter plugged in. Note that wlan0 is my internal wireless adatper, while wlan1 is my external wireless adapter.

What I have tried:

  1. I uninstalled Network Manager and installed WICD, but the problem remains.

  2. I followed http://www.hitxp.com/articles/software/ubuntu-fix-slow-wireless-internet-connection-speed-upgrading-11-04-natty-narwhal/, to add /sbin/iwconfig wlan0 power off to /etc/pm/power.d/wireless. That doesn't solve the problem (maybe make it less happen, but I am not sure.)

  3. I followed https://askubuntu.com/a/541118/1471

    • add options iwlmvm power_scheme=1 to /etc/modprobe.d/iwlmvm.conf
    • add options iwlwifi bt_coex_active=Y led_mode=1 swcrypto=1 11n_disable=1 to /etc/modprobe.d/iwlwifi.conf

    That doesn't solve the problem (maybe make it less happen, but I am not sure.)

  4. I followed Very slow, intermittent WiFi speeds with 14.04 and Intel PRO/Wireless 5100 AGN [Shiloh], to add @reboot iwconfig wlan0 rate 54M to crontab by sudo crontab -e. That doesn't solve the problem (maybe make it less happen, but I am not sure.)

  5. 1-4 were tried before I upgraded kernel to Vivid's kernel 4.0 on Trusty. But after I made the kernel upgrade two days ago, the problem remains (I am not sure if that makes the problem less frequent.) The settings in 1-4 seem to apply to all installed kernel versions.

  6. when my internal one doesn't work, I try to plug in my external usb wireless adapter. But the external one doesn't work either.
    I remember with Trusty's kernel, most of the time, the external one worked when the internal one didn't, but recently (before kernel upgrade) became not working either.

    Sometimes I wonder if it is more realistic and easier to first make the external USB adapter work. It worked most of time until sometime before kernel upgrading and probably during I made those settings. Will the external one be easier to solve than the internal one?

04-21-2015

My wireless connection automatically drops once in a while.
Once that happens, I use WICD to reconnect to the wireless network, which shows that it puts down and up wireless interface. I wonder if there is some solution and/or reason?

The problem happens both before and after I recently installed 64bit generic kernel 4.0 from http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.0-vivid/, on Trusty (i.e. Ubuntu 14.04), following http://ubuntuhandbook.org/index.php/2015/04/upgrade-to-linux-kernel-4-0-in-ubuntu/.

My output of running the script http://dl.dropbox.com/u/57264241/wireless_script is here. I run the script after reconnection by WICD, not during disconnection.

Although now I can reconnect, I worry if my previous wireless disable problem with Trusty's own kernel (i.e. before I install Vivid's kernel 4.0 ) still exists (and I just wait for that to happen, and I don't know a way to reconnect if that happens).

Thanks.

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