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simonleu

Member

Registered: 2015-03-17

Posts: 1

Thinkpad X220: bad wlan connection when docked and lid closed

Dear forum

I use a Lenovo ThinkPad X220. I have no trouble with the wlan connection when i use the notebook alone. The wlan connection is also stable when i use the notebook plugged in the dockingstation with the lid open. But when I use the notebook plugged in the dockingstation with the lid closed my wlan connection drops regularely to about 2 Mbps and gets very unstable.

The ThinkPad uses the Intel Centrino Advanced-N 6205 wlan network controller:

$ lspci | grep 6205
03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)

The network controller uses the iwlwifi driver, that comes with the current linux-firmware package:

$ pacman -Ss linux-firmware
core/linux-firmware 20150206.17657c3-1 [Installiert]
    Firmware files for Linux

I didn't change any options of the kernel module, everything runs in default mode:

$ modinfo -p iwlwifi
swcrypto:using crypto in software (default 0 [hardware]) (int)
11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint)
amsdu_size_8K:enable 8K amsdu size (default 0) (int)
fw_restart:restart firmware in case of error (default true) (bool)
antenna_coupling:specify antenna coupling in dB (default: 0 dB) (int)
wd_disable:Disable stuck queue watchdog timer 0=system default, 1=disable (default: 1) (int)
nvm_file:NVM file name (charp)
uapsd_disable:disable U-APSD functionality (default: Y) (bool)
bt_coex_active:enable wifi/bt co-exist (default: enable) (bool)
led_mode:0=system default, 1=On(RF On)/Off(RF Off), 2=blinking, 3=Off (default: 0) (int)
power_save:enable WiFi power management (default: disable) (bool)
power_level:default power save level (range from 1 - 5, default: 1) (int)
fw_monitor:firmware monitor - to debug FW (default: false - needs lots of memory) (bool)

At first I thought, the problem could be caused by the KDE power saving settings. I changed the settings, so nothing happens when I close the lid (no hibbernation or screen lock or something like that), but without success (the wlan connection is still unstable under the described circumstances).

Also dmesg shows nothing that points out a problem (as far as I can see):

$ dmesg | grep iwlwifi
[   19.688522] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[   19.688679] iwlwifi 0000:03:00.0: irq 31 for MSI/MSI-X
[   19.696095] iwlwifi 0000:03:00.0: loaded firmware version 18.168.6.1 op_mode iwldvm
[   19.718023] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled
[   19.718027] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS disabled
[   19.718028] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[   19.718029] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Advanced-N 6205 AGN, REV=0xB0
[   19.718145] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   19.753757] iwlwifi 0000:03:00.0 wlp3s0: renamed from wlan0
[   20.128443] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   20.128652] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[   20.403905] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   20.404212] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[   68.922975] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   68.923192] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0

So I have no idea where this strange behaviour comes from (only wild guesses: buildfactor, antenna orientation,...).

Any help would be really appreciated.