Ubuntu – How to resolve wireless disconnect problem in Atheros ath9k

All right, looks like I found a solution: I tried using laptop+TP-Link TL-WN722N with another router and suddenly the wifi stick was able to deliver the expected performance.

In the end I managed to narrow it down to a setting of my router called "WMM" (also called Wifi-Multi-Media or Wireless-Multimedia-Extensions or WME).

If I disable WMM in my router, the wifi stick delivers the expected 25 Mbits/sec that my internet connection is capable of.

However, please note that if you disable WMM/WME in your router settings your router will reduce its wifi speed to 54 Mbits/sec (IEEE 802.11g).

Summary:

On Windows the TP-Link TL-WN722N works as expected.

On Linux the TP-Link TL-WN722N only works correctly with IEEE 802.11g. If your TP-Link TL-WN722N is slow, you need to disable WMM or WME in your router settings.

While I might not provide the exact solution to the problem right now, because your question is missing relevant information, here's some things you can do to troubleshoot the problem and perhaps include them into the question, so that other users can help you.

What can you include into your question?

• Script output from My wireless/WiFi connection does not work. What information is needed to diagnose the issue?
• Ouput of /var/log/syslog. Try reproducing the problem and note the time when you do it. After you go through the whole process, read the syslog. The recent events are all at the end of file, so you might want to do something like cat /var/log/syslog | tail -n50 to list last 50 lines in that file, but you can change that number as needed.
• Output of lsmod ( perhaps a driver isn't loading properly );
• Output of dmesg
• Output of rfkill list all

Possible issues:

Your ethernet works, but wireless doesn't. So it may well be issue with wireless card ( failiing hardware ), with wireless drivers, or wireless configuration. But until we know what's in your syslog, we probably won't be able to pin-down the issue. There are wireless dongles, which you could use to test whether or not this is wireless card issue, but the better way IMHO would be to boot on a live USB, and see if that works.