[Bug 600942] [NEW] Atheros AR5008 on Ubuntu 10.04 with either ath9k or ndiswrapper drivers cause excessive CPU wakeup

[Ivan Potapenko]

Public bug reported:

I have recently tried to upgrade my netbook with an Atheros AR5008 Wifi
card from Ubuntu 8.04 to 10.04. This was done by a clean install (not
the Ubuntu dist-upgrade procedure).

Everything worked fine except for the wireless card. When using 8.04 I
used ndiswrapper with great success. Now, both the ndiswrapper and ath9k
drivers give me a very strange problem: They wake up CPU excessively
making the whole system slow and unresponsive. This usually happens
after I have connected to a network and try to transfer any substantial
amount of data.

If you take a look at powertop output you can see that wakeup number
usually is below approximately 1500 (even with heavy usage of wifi with
Ubuntu 8.04). However on Lucid I get often numbers ranging from 5000 to
15000 which is ridiculously high.

Once the excessive wakeups have begun, no iwconfig power saving
configuration or even rmmod-ing the driver helps. Installing wireless
from backports does not alleviate the problem either.

This is also present on most other major distributions (OpenSUSE, Fedora
Core) as well as Ubuntu derivatives (Mint etc). The only exception is
Arch which uses a newer kernel version (which may or may not have
something to do with the problem).

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: linux (Fedora)
     Importance: Undecided
         Status: New

** Affects: linux (openSUSE)
     Importance: Undecided
         Status: New


** Tags: ath9k kernel-bug ndiswrapper wireless

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Atheros AR5008 on Ubuntu 10.04 with either ath9k or ndiswrapper drivers cause excessive CPU wakeup
https://bugs.launchpad.net/bugs/600942
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