Description of problem:
Ethernet connection gets disconnected at random apparently without any reason. I have tried the following command to restart my ethernet connection,
sudo service network-manager restart
though it never solved the issue. Every time I have to restart my system to get the connection back.
Details of my Ethernet card:
$ lspci -nnk | grep -iA2 net
06:00.0 Network controller [0280]: Qualcomm Atheros AR9285 Wireless Network Adapter (PCI-Express) [168c:002b] (rev 01)
Subsystem: Lenovo Device [17aa:30a1]
Kernel driver in use: ath9k<br>
07:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller [10ec:8136] (rev 02)
Subsystem: Lenovo Device [17aa:392e]
Kernel driver in use: r8169
My system: Ubuntu 14.04 LTS 64bit on Lenovo ideapad z560.
OBSERVATION: It happens more frequently when I make calls in skype or hangout. It seems that heavy usage of Ethernet is causing the disconnection.
Debug steps tried so far:
I found a post Wired Network is not stable in ubuntu 13.04 (64-bit) have something similar problem description as mine but not exactly. Following the solution given in that post, I installed and tried to use an older kernel linux-image-3.5.0-27-generic
. But the same problem persisted there.
At the same time I am not sure if it is a hardware related issue as this never happened with Windows 7 which I was using before. I did a lot of googling but could not find a solution except a few about older versions and bug report.
As a hint to look into dmesg
[ thanks to @noleti ], I found the following:
$ dmesg -T | grep eth0 [Sat May 2 19:52:37 2015] r8169 0000:07:00.0: eth0: RTL8102e at 0xffffc90000348000, 88:ae:1d:3a:ec:ff, XID 04e00000 IRQ 41 [Sat May 2 19:52:45 2015] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [Sat May 2 19:52:51 2015] r8169 0000:07:00.0: eth0: link down [Sat May 2 19:52:51 2015] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [Sat May 2 19:52:51 2015] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [Sat May 2 19:52:56 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 19:52:56 2015] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [Sat May 2 20:09:01 2015] NETDEV WATCHDOG: eth0 (r8169): transmit queue 0 timed out [Sat May 2 20:09:01 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:09:13 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:09:19 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:09:31 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:10:13 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:10:55 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:12:07 2015] r8169 0000:07:00.0: eth0: link up [Sat May 2 20:13:49 2015] r8169 0000:07:00.0: eth0: link up
After the event as shown in dmesg
output my connection is lost.
NETDEV WATCHDOG: eth0 (r8169): transmit queue 0 timed out