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

[Ivan Potapenko]

Some further observations: There are neither errors nor warnings in any
of the system logs. As I stated earlier, rmmod-ing the given wireless
driver (be it ndiswrapper or ath9k) does not help once the problem
arises. However, suspending to RAM and then resuming fixes the problem
until it inevitably reoccurs when trying to transfer some data over the
wifi. Strangely though, switching off the wireless card (either with the
physical hardware switch on the side of the laptop or with the function
keys) does not help.

I have now compiled two custom kernels: 2.3.34 and 2.3.35-rc3. Kernel
configs were copied from the Ubuntu stock kernel (2.3.32-23) and the
rest of the configuration was left at default values (answering "yes" to
all queries by "make oldconfig"). From what I can see the problem is
almost gone in both of these two kernels, however it does occur randomly
after prolonged periods of wifi use.

** Description changed:

  I have recently tried to upgrade my netbook (edit: it is a Notus A12)
- with an Atheros AR5008 Wifi card from Ubuntu 8.04 to 10.04 (edit: lsusb
- -v is now attached below). This was done by a clean install (not the
- Ubuntu dist-upgrade procedure).
+ 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).

-- 
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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