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-   -   ath9k stuttering (

htedrom 07-13-2011 01:34 AM

ath9k stuttering
Hi all,

usually the wireless on my laptop is fine except at the coffee shop where I study a lot. Get shoddy connection, but more troubling than that, sometimes I can't get an IP from the router at all while my friends are browsing away, and a reboot usually fixes it. Even more troubling is that sometimes i'll get little CPU "hiccups" when the connection is poor. They roughly correlate to these in dmesg:

[ 947.632309] ath9k: RX failed to go idle in 10 ms RXSM=0xdeadbeef
[ 954.851954] ath9k: timeout (100000 us) on reg 0x806c: 0xdeadbeef & 0x01f00000 != 0x00000000
[ 954.852125] ath9k: RX failed to go idle in 10 ms RXSM=0xdeadbeef

etc, etc.

when I get this hiccups it will stutter my music player regardless of its nice priority. I try unloading and loading ath9k but that doesn't change anything. Anyone have any ideas?

anewson@melvin:~$ uname -r
anewson@melvin:~$ cat /etc/issue
Ubuntu 10.04.2 LTS \n \l

markush 07-14-2011 10:48 AM

Hello htedrom,

I'm no expert for Ubuntu, but if it was Windows I would say: check if there is any "Energy-Saving-Option" enabled for the Wlan-adapter. I don't know if Ubuntu comes with such options in their programs.

Edit: I have the same wireless-adapter in my laptop and I've looked in Win 7 (which I've also installed on the machine) there is an Energysavemode in Windows. Maybe it is really used in Linux as well.


htedrom 07-18-2011 08:21 PM

hey markus,

there is a power management feature for the card, but I disabled it when the problem started.


wlan0    IEEE 802.11bgn  ESSID:"grind" 
          Mode:Managed  Frequency:2.437 GHz  Access Point: 5C:D9:98:5C:B5:0C 
          Bit Rate=11 Mb/s  Tx-Power=20 dBm 
          Retry  long limit:7  RTS thr:off  Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=50/70  Signal level=-60 dBm 
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

htedrom 07-21-2011 02:40 AM

just an update: the CPU spikes are in the [phyX] process (where X=number that increases, I think when I unload/reload driver), which is a network layer or something? Not sure if that's any help.

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