{"id":164,"date":"2022-01-24T18:57:00","date_gmt":"2022-01-24T17:57:00","guid":{"rendered":"https:\/\/bowfinger.de\/blog\/?p=164"},"modified":"2022-01-24T10:58:26","modified_gmt":"2022-01-24T09:58:26","slug":"ath-ath9k-cfg80211-being-weird-regdomain-and-wireless","status":"publish","type":"post","link":"https:\/\/bowfinger.de\/blog\/2022\/01\/ath-ath9k-cfg80211-being-weird-regdomain-and-wireless\/","title":{"rendered":"ath\/ath9k\/cfg80211 being weird (regdomain and wireless)"},"content":{"rendered":"\n

Upon upgrading my Kernel on my Ubuntu 20.04 LTS to the HWE stack, I ran into the issue that Wifi stopped working.<\/p>\n\n\n\n

Turns out, it only refused to listen\/transmit on channels 12 and higher. My router was using channel 13, so no luck.<\/p>\n\n\n\n

After some research, I found that you can set the Wifi stack to obey your country’s regulatory requirements. In Germany, channels 12 and 13 are fine to use.<\/p>\n\n\n\n

Others had the same problem back in the day<\/a>, apparently. But the proposed solution did not work or did not work anymore.<\/p>\n\n\n\n

In my case, with a Qualcomm Atheros AR93xx using ath9k<\/code>, editing \/etc\/default\/crda<\/code> setting REGDOMAIN=DE<\/code> or trying to use iw reg set DE<\/code> did not help.<\/p>\n\n\n\n

What helped after all was setting ieee80211_regdom=DE<\/code> when loading the cfg80211<\/code> module. So, I somehow doubt that the issue was the ath9k<\/code> module itself.<\/p>\n\n\n\n

Try this:<\/p>\n\n\n\n

Create \/etc\/modprobe.d\/cfg80211.conf<\/code> with content:<\/p>\n\n\n\n

options cfg80211 ieee80211_regdom=DE<\/code><\/pre>\n\n\n\n
Obviously, you set it to the 2-digit ISO code of the place you live at.<\/p>\n\n\n\n
For Germany, this results in the expected 2.4 GHz band channel list (iw list | grep -A 15 Frequencies:<\/code>):<\/p>\n\n\n\n
* 2412 MHz [1] (20.0 dBm)\n* 2417 MHz [2] (20.0 dBm)\n* 2422 MHz [3] (20.0 dBm)\n* 2427 MHz [4] (20.0 dBm)\n* 2432 MHz [5] (20.0 dBm)\n* 2437 MHz [6] (20.0 dBm)\n* 2442 MHz [7] (20.0 dBm)\n* 2447 MHz [8] (20.0 dBm)\n* 2452 MHz [9] (20.0 dBm)\n* 2457 MHz [10] (20.0 dBm)\n* 2462 MHz [11] (20.0 dBm)\n* 2467 MHz [12] (20.0 dBm)\n* 2472 MHz [13] (20.0 dBm)\n* 2484 MHz [14] (disabled)<\/code><\/pre>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Upon upgrading my Kernel on my Ubuntu 20.04 LTS to the HWE stack, I ran into the issue that Wifi stopped working. Turns out, it only refused to listen\/transmit on channels 12 and higher. My router was using channel 13, so no luck. After some research, I found that you can set the Wifi stack…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[17,16],"tags":[27],"class_list":["post-164","post","type-post","status-publish","format-standard","hentry","category-hardware","category-linux","tag-wifi"],"_links":{"self":[{"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/posts\/164","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/comments?post=164"}],"version-history":[{"count":1,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/posts\/164\/revisions"}],"predecessor-version":[{"id":165,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/posts\/164\/revisions\/165"}],"wp:attachment":[{"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/media?parent=164"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/categories?post=164"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bowfinger.de\/blog\/wp-json\/wp\/v2\/tags?post=164"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}