From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alberto Mardegan Date: Mon, 25 May 2015 07:25:03 -0000 Subject: [ath9k-devel] AR9271-based device regularly loses packets for 18 seconds Message-ID: <5562CCA2.2020902@users.sourceforge.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org Hi there! I bought a Tp-Link TL-WN721N, which appears under lsusb as: Bus 008 Device 003: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n The device worked out of the box (kernel version is 3.16.0-38-generic #52~14.04.1-Ubuntu), but the connection goes completely silent from time to time, for about 18 seconds. I've kept a long running "ping -D google.com" process, and I've seen that every two minutes 17 or 18 ping packets are lost. I won't attach the whole output of the ping command, I'll just show you the last lines *before* the lost packets: [1432536493.004202] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=829 ttl=53 time=5.55 ms [...] [1432536613.152717] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=949 ttl=53 time=2.47 ms [1432536618.838819] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=954 ttl=53 time=653 ms [...] [1432536732.424766] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=1068 ttl=53 time=2.91 ms [...] [1432536852.722089] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=1188 ttl=53 time=2.44 ms [...] [1432536973.016098] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=1308 ttl=53 time=4.92 ms [...] [1432537093.304302] 64 bytes from cache.google.com (87.245.198.34): icmp_seq=1428 ttl=53 time=2.28 ms As you can see, with an exception between rows 2 and 3, all the other timestamps differ by 120 seconds, aka two minutes. Other computers running on the same network don't experience such issues, and when I've attached the adaptor to another PC (also running Ubuntu 14.04), I've experienced the same problems. It looks to me that this behaviour is probably triggered by the driver of by the firmware. Do you have any idea of what might be causing this? Is this a known issue? Ciao, Alberto