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Re: big problem with TP-LINK WiFi card



On Sat, 10 Mar 2012 23:33:02 +0100, Bernard wrote:

> Camaleón wrote:
   
>> There are many issues reported for system freezes regarding that kernel
>> module (ath9k), there is even a documented bug at the Linuxwireless
>> site:
>>
>> http://linuxwireless.org/en/users/Drivers/ath9k/bugs#Hangs_with_PCI_devices_and_SMP_systems
>>
>> And even on Debian BTS:
>>
>> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=611946
>>
>> I would try with an updated kernel.
>>
>>
> Thanks for this information. I might end up updating the kernel, but at
> this stage I am still trying to understand what happens and if there is
> another way to go around. 

Installing an updated kernel will not hurt, you can keep the current one 
(Debian Squeeze stock) and compiling (or installing from backports) a new 
one.

> I also have an ASUS laptop on which I installed Debian Squeeze on a
> dual boot together with MSWIN XP. This laptop allows a wireless
> connexion, even though nothing was installed other than what already
> existed on "MSWIN-XP". Wireless connexions are fully operational, even
> though they are often active for hours. I searched about the chipset
> used. It appeared to be the same as on the Desktop !
> 
> lspci on the laptop (the one that works fine) says :
> 
> Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-express
> rev 01

This is a PCI-Express based card.
 
> (while on the Desktop where no wireless connexion can operate for any
> longer than one or two minutes without system freeze, this is a AR9287
> Wireless Network Adapter, TP-LINK TL-WN751ND)

This is a PCI based card.

> As stated, both machines are on Squeeze. On the laptop where everything
> works fine,  kernel is 2.6.32-5-686 (Debian 2.6.32.30), while it is
> Debian 2.6.32-41 on the problematic Desktop.

The afore mentioned bug was present on PCI cards while not in PCI-Express 
based cards, maybe that's the difference.

***
Hangs with PCI devices and SMP systems

This issue was due to a hardware limitation on our PCI devices whereby our 
device's FIFO queue got filled up and caused a loop. This issue is only present 
on our 11n PCI devices, its not present on our PCI-express devices nor our 
legacy 802.11abg devices.
***

> I carried a few more tests on the problematic Desktop. I tested 'Wicd'
> instead of 'NetworkManager'. 

(...)

The problem is on the kernel module, I can't see how user space tools such can 
cope with this unless getting an updated kernel/driver. 

> If I were to upgrade kernels, which kernel would you recommend ?

I would try with the backports one, as it's easier to install. If that also fails, I 
would compile the latest stable kernel from sources available at kernel's site 
(now 3.2.9).

Greetings,

-- 
Camaleón


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