2

I've noticed that my WiFi would suddenly disconnected and not listed in the available WiFi network list. I have to turn on airplane mode/disable WiFi to get it connected back or listed in the list. The other way is to go to Connect to Hidden WiFi network and select my network from the list. A quick check on the listed question says mostly a realtek driver issue but I'm using Qualcomm Atheros. Below is my lshw -c network

*-network               
       description: Wireless interface  
       product: AR9285 Wireless Network Adapter (PCI-Express)  
       vendor: Qualcomm Atheros  
       physical id: 0  
       bus info: pci@0000:43:00.0  
       logical name: wlan0  
       version: 01  
       serial: 78:e4:00:98:42:7c  
       width: 64 bits  
       clock: 33MHz  
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless  
       configuration: broadcast=yes driver=ath9k driverversion=3.19.0-28-generic firmware=N/A ip=192.168.1.67 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn  
       resources: irq:19 memory:d0700000-d070ffff  
1

The fact that it works fine for a period seems to indicate faulty power saving mode in the Ath9k driver. You can try to disable this with the following methods.

Disable WiFi Power Saving

Temporary

sudo iwconfig wlan0 power off

(or)

sudo modprobe -r ath9k
sudo modprobe ath9k ps_enable=0

Permanent

sudo touch /etc/modprobe.d/ath9k.conf
sudo scratch-text-editor /etc/modprobe.d/ath9k.conf

Add options ath9k ps_enable=0 as the last line

  • Shame. You could also try disabling hw encryption as mentioned in this question. Might pay for you to examine the contents of dmesg and /var/log/syslog immediately after a disconnect and post anything that seems related to the WiFi – elmato Sep 13 '15 at 14:36
  • unfortunately the solution does not work. I still experienced the wifi disconnection. When I use the command sudo iwconfig wlan0 power off, I would get this Error for wireless request "Set Power Management" (8B2C) : SET failed on device wlan0 ; Operation not supported. – Frozzbyte Sep 13 '15 at 14:44
  • Will check on dmesg and syslog if it occurs again. What should I be looking for in the syslog? – Frozzbyte Sep 13 '15 at 14:50
  • Running sudo modprobe -r ath9k and sudo modprobe ath9k ps_enable=0 really screwed up my wifi just now. The wifi connection kept on turn on, scanning and turn off. Had to reboot to get it back up again. – Frozzbyte Sep 13 '15 at 15:13
  • Good thing you didn't apply the permanent solution then. ;p In syslog you are looking for lines containing wlan0, Ath9k, wpasupplicant or networkmanager (amongst other things) corresponding with the time the issue occurs. If you run dmesg with the -T flag (dmesg -T) the timestamps will be in the same format as syslog. If in doubt post them in their entirety to pastebin or somewhere and just link to that. – elmato Sep 13 '15 at 15:25

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