Hello All, I've noticed unexpected transmissions from the AR9170 while in monitor mode and using tcpdump (and sometimes without tcpdump running). These transmissions degrade (pretty significantly) performance of other STA/AP on the channel (as seen by iperf going from 60mbit/s to almost nill). As best I can tell these transmissions never coalesces into an actual frame in the air (at least not one I'm able to pick up with a second different adapter in monitor mode). Are there any known reasons/bugs on this? Is there anyway to completely silence the transmitter of the AR9170 while still allowing reception? Some additional information that may give some context: - This seems to happen over a wide range of releases of compat wireless I've tried, I've tested between compat wireless 2.6.39-rc6-1 and 2012-7-03, various drivers and firmware (the latest being driver 1.9.4 and firmware 1.9.5). I've also seen the problem across multiple AR9170 adapters, as well as different linux hosts. - I've put a few printk's in the carl driver & stubbed out (somewhat blindly) some of the tx functions in wlan.c in the firmware to see if I could silence or get a clue on whats going on, with not much success. The problem still occurred (No prink's told me the kernel wasn't actively generating any pkts). - Seems like the transmissions only occur when monitoring 802.11n speeds. (That is if I manual configure the AP to 54mbit/s, I don't see the issue). Happens in both 2.4 or 5ghz band. - I was able to also observe this behavior with a single ping. Only seemed to occur with larger ICMP pings (would occur with -s 2000 pings, but not a standard (56 byte) ping). - Along with iperf degradation, I've verified transmissions with a spectrum analyzer. Thank you, Marco Fonseca -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
