Re: Odd network behaviors with an Intel Wireless 7260

[Emmanuel Grumbach <egrumbach@gmail.com>]

Hi,


On 04/25/2014 02:03 AM, Pierre Bourdon wrote:
> Hi linux-wireless folks,
> 
> I have been getting some weird network behaviors with my Intel
> Wireless 7260 adapter that I cannot explain by anything else than a
> driver/firmware bug. I'm out of ideas on how to debug this issue.
> 
> My network configuration is fairly basic: IPv4 over 802.11n,
> AP/default gateway is 192.168.0.1, my Intel 7260 STA is 192.168.0.2.
> Several AP/gateway hardware and software have been tested and have
> shown the same problem.
> 
> On 192.168.0.2 I am constantly running some ICMP pings to 192.168.0.1
> and 8.8.8.8. Randomly, the pings from 192.168.0.2 to 8.8.8.8 start
> failing (responses never received) while the pings to 192.168.0.1
> continue to succeed without any trouble. When tcpdumping on the
> gateway, I see the pings to 8.8.8.8 being successfully forwarded and
> responses being sent back to the STA (so this is not a routing issue
> on the gateway - and again, I've tested several combinations of hw/sw
> on the gateway).
> 
> Another example: my TCP sessions on the Intel 7260 STA to the internet
> will start randomly freezing, but my TCP sessions going through
> tunnels on another LAN host (let's say, 192.168.0.3) to the internet
> will work fine.
> 
> After 30s-1min30 the problem fixes itself and packets start being
> received by the STA again.
> 
> I only see this from the Intel 7260 host and not from any other WLAN
> device connected to the AP, which is another strong evidence that the
> issue is on the STA side.
> 
> I've shared this with some other people using an Intel 7260 adapter on
> Linux and found someone having a similar issue. I'm not sure how
> widespread it is and could not find an existing bug report.
> 
> What are the next steps to get useful debugging information out of
> this issue? I unfortunately do not have the required hardware to do
> monitor-mode sniffing of what's happening at the L2 level.
> 

Thank you very much for this very detailed report.
1) can you try with power save disabled?
   sudo iw wlan0 set power_save off
2) if 1) helps, can you try https://git.kernel.org/cgit/linux/kernel/git/iwlwifi/iwlwifi-fixes.git/commit/?id=a82dda6cd492b8c88952be6f6527f3656f7ac585.

Thanks