$ lsmod | grep iwl
iwldvm                232283  0 
mac80211              652718  1 iwldvm
iwlwifi               179412  1 iwldvm
cfg80211              494362  3 iwlwifi,mac80211,iwldvm

I heard that iwlwifi is the module of my wireless driver. What is iwldvm? Why does it use iwlwifi? After I unload iwldvm, my wireless adpter can't scan available wireless networks.

Why is mac80211 loaded, given that my laptop is not mac?

Is there something with the modules already loaded or not yet loaded, which may potentially cause wireless connection problem?

My OS is 64bit Ubuntu 14.04 on Thinkpad T400, and wireless controller/adapter is

       description: Wireless interface
       product: PRO/Wireless 5100 AGN [Shiloh] Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=3.16.0-34-generic firmware= build 33692 ip= latency=0 link=yes multicast=yes wireless=IEEE 802.11abg
       resources: irq:49 memory:f4200000-f4201fff

mac here doesn't have any relation to Macs: MAC stands for Media Access Control. The module described in details here and it just provides a framework for Wi-Fi drivers to build upon.

Also, cfg80211 provides the configuration layer. As I understand it, iwldvm just provides lower-level functionality for iwlwifi (thus the dependency) and other Intel WLAN device drivers.

For the record, I have a Intel 1030 wireless and this is what I have (looks similar to what you have):

$ lsmod|grep iwl
iwldvm                184887  0 
mac80211              648753  1 iwldvm
iwlwifi               169263  1 iwldvm
cfg80211              476584  3 iwlwifi,mac80211,iwldvm
  • Thanks. Are my wireless driver modules just the four modules listed? – Tim Apr 13 '15 at 17:28
  • @Tim Judging from my machine (which has a Intel wireless card, too) I think that yes. – Renan Apr 13 '15 at 17:29
  • According to your reply, is it correct that the modules are build on one another in the following levels from low to high: mac80211 -> iwldvm -> iwlwifi -> cfg80211? But the "used by" relation between the modules shown by lsmod indicates: cfg80211 -> mac80211, iwlwifi -> iwldvm? – Tim Apr 13 '15 at 17:29

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