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Strange Problem: Network stops when TV Turns off
http://forums.linhes.org/viewtopic.php?f=2&t=17345
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Author:  Greg Frost [ Wed Nov 28, 2007 12:53 pm ]
Post subject:  Strange Problem: Network stops when TV Turns off

I have a very strange problem. When I turn my TV off, my network stops working. I am using the on-board network on this hardware:

ASUS P5B motherboard
(onboard Realtek RTL8111/8168B PCI Express Gigabit Ethernet controller)
3Ghz Pentium D
nVidia Corporation G70 [GeForce 7600 GS] (rev a1) - pci express
2x DVICO FusionHDTV PCI tuners
Samsung LCD TV connected via DVI->HDMI cable

If I set a ping of my rounter going and then turn off my TV and then turn it back on again I see this:

In this case I had to turn it off 3 times (note the threee delayed blocks of ping responses) before the network stopped alltogether.
Code:
root@mythtv:~# ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=0.356 ms
64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.382 ms
64 bytes from 10.1.1.1: icmp_seq=3 ttl=64 time=0.377 ms
64 bytes from 10.1.1.1: icmp_seq=4 ttl=64 time=0.361 ms
64 bytes from 10.1.1.1: icmp_seq=5 ttl=64 time=3950 ms
64 bytes from 10.1.1.1: icmp_seq=6 ttl=64 time=2950 ms
64 bytes from 10.1.1.1: icmp_seq=7 ttl=64 time=1950 ms
64 bytes from 10.1.1.1: icmp_seq=8 ttl=64 time=950 ms
64 bytes from 10.1.1.1: icmp_seq=9 ttl=64 time=0.375 ms
64 bytes from 10.1.1.1: icmp_seq=10 ttl=64 time=0.403 ms
64 bytes from 10.1.1.1: icmp_seq=11 ttl=64 time=0.369 ms
64 bytes from 10.1.1.1: icmp_seq=12 ttl=64 time=0.384 ms
64 bytes from 10.1.1.1: icmp_seq=13 ttl=64 time=0.420 ms
64 bytes from 10.1.1.1: icmp_seq=14 ttl=64 time=0.408 ms
64 bytes from 10.1.1.1: icmp_seq=15 ttl=64 time=0.399 ms
64 bytes from 10.1.1.1: icmp_seq=16 ttl=64 time=0.384 ms
64 bytes from 10.1.1.1: icmp_seq=17 ttl=64 time=0.379 ms
64 bytes from 10.1.1.1: icmp_seq=18 ttl=64 time=0.359 ms
64 bytes from 10.1.1.1: icmp_seq=19 ttl=64 time=0.358 ms
64 bytes from 10.1.1.1: icmp_seq=20 ttl=64 time=0.374 ms
64 bytes from 10.1.1.1: icmp_seq=21 ttl=64 time=0.357 ms
64 bytes from 10.1.1.1: icmp_seq=22 ttl=64 time=0.364 ms
64 bytes from 10.1.1.1: icmp_seq=23 ttl=64 time=0.361 ms
64 bytes from 10.1.1.1: icmp_seq=24 ttl=64 time=0.359 ms
64 bytes from 10.1.1.1: icmp_seq=25 ttl=64 time=0.357 ms
64 bytes from 10.1.1.1: icmp_seq=26 ttl=64 time=0.350 ms
64 bytes from 10.1.1.1: icmp_seq=27 ttl=64 time=5659 ms
64 bytes from 10.1.1.1: icmp_seq=28 ttl=64 time=4659 ms
64 bytes from 10.1.1.1: icmp_seq=29 ttl=64 time=3659 ms
64 bytes from 10.1.1.1: icmp_seq=30 ttl=64 time=2659 ms
64 bytes from 10.1.1.1: icmp_seq=31 ttl=64 time=1657 ms
64 bytes from 10.1.1.1: icmp_seq=32 ttl=64 time=656 ms
64 bytes from 10.1.1.1: icmp_seq=33 ttl=64 time=0.378 ms
64 bytes from 10.1.1.1: icmp_seq=34 ttl=64 time=0.358 ms
64 bytes from 10.1.1.1: icmp_seq=35 ttl=64 time=0.365 ms
64 bytes from 10.1.1.1: icmp_seq=36 ttl=64 time=0.381 ms
64 bytes from 10.1.1.1: icmp_seq=37 ttl=64 time=0.399 ms
64 bytes from 10.1.1.1: icmp_seq=38 ttl=64 time=0.365 ms
64 bytes from 10.1.1.1: icmp_seq=39 ttl=64 time=0.363 ms
64 bytes from 10.1.1.1: icmp_seq=40 ttl=64 time=0.362 ms
64 bytes from 10.1.1.1: icmp_seq=41 ttl=64 time=0.369 ms
64 bytes from 10.1.1.1: icmp_seq=42 ttl=64 time=0.371 ms
64 bytes from 10.1.1.1: icmp_seq=43 ttl=64 time=0.363 ms
64 bytes from 10.1.1.1: icmp_seq=44 ttl=64 time=0.352 ms
64 bytes from 10.1.1.1: icmp_seq=45 ttl=64 time=0.362 ms
64 bytes from 10.1.1.1: icmp_seq=46 ttl=64 time=0.341 ms
64 bytes from 10.1.1.1: icmp_seq=47 ttl=64 time=0.361 ms
64 bytes from 10.1.1.1: icmp_seq=48 ttl=64 time=8171 ms
64 bytes from 10.1.1.1: icmp_seq=49 ttl=64 time=7170 ms
64 bytes from 10.1.1.1: icmp_seq=50 ttl=64 time=6170 ms
64 bytes from 10.1.1.1: icmp_seq=51 ttl=64 time=5171 ms
64 bytes from 10.1.1.1: icmp_seq=52 ttl=64 time=4171 ms
64 bytes from 10.1.1.1: icmp_seq=53 ttl=64 time=3171 ms
64 bytes from 10.1.1.1: icmp_seq=54 ttl=64 time=2171 ms
64 bytes from 10.1.1.1: icmp_seq=55 ttl=64 time=1170 ms
64 bytes from 10.1.1.1: icmp_seq=56 ttl=64 time=171 ms
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available

Doing this brings the network back:
Code:
ifdown eth0 ; ifup eth0
I have no idea where to start with this problem!!

Author:  mad_paddler [ Wed Nov 28, 2007 4:13 pm ]
Post subject: 

Very strange problem!!

Is there anything in the logs when you're pinging and turn the TV off?

Author:  tjc [ Wed Nov 28, 2007 6:56 pm ]
Post subject: 

Just some random ideas...

Make sure your network cable is as far away from your video cable and TV as possible. Cross talk and surges can produce some impressive results.

Also some AV equipment comes with extra power outlets which are often switched, you didn't plug some part of your networking equipment into one of these did you?

Author:  Greg Frost [ Fri Nov 30, 2007 5:06 am ]
Post subject: 

I think the issue was due to a bug in the Realtek NIC driver. It didnt seem to cope properly with sharing IRQs (which is a requirement with my P5B motherboard). Upgrading the kernel to 2.6.22 seems to have fixed it.

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