[SOLVED] AR8161 NIC in ASUS N56VZ: Connection loss

[XmainframeX]

Hi everybody,

I'm experiencing weired problems with the AR8161 NIC built into my laptop: After working fine at the beginning, no incoming packets are received anymore after some time (4 seconds to 2 minutes). I tested this with wireshark.
I can only avoid this problem by booting the laptop with the network cable plugged in and having all other network devices disabled before the last shutdown.

I have tested different configurations including old kernels with backports/compat-drivers and newer kernels including the alx driver. These are the results

• + Windows
  
• + Kernels before 3.7 in Gentoo
  
• + Debian 7.2 with kernel 3.2
  
• - Kernels from 3.7 on with backports in Gentoo
  
• - Kernels including the alx driver in Gentoo
  

Some other observations:

• When the laptop is booted with Wifi enabled, the wired network connection stays for about 2 minutes
  
• When the connection is gone, I can bring it back for a few seconds (observed 4-30s) by rmmod alx; modprobe alx
  
• The connection seems to be lost faster if more data is transferred
  

Do you have any suggestions what else I could try? Any additional information needed?
Does anybody know where to find the compat-drivers source code for kernel 3.6 and 3.7 to compare them? Found the repository but no tags/branches referring to kernel versions before 3.10...

Thx in advance!

[XmainframeX]

While searching for differences in the alx driver source between compat-wireless-3.6 and compat-drivers-3.8, I stumbled over some changed variable names for the RX buffer size calculation. In addition, I noticed that RX buffer size calculation differs between > and <= 7*1024 bytes

So I decided to try the other code path and changed my mtu from 14xx to 8192 bytes. Since then, everything is running smoothly...