[SOLVED] Persistent Ethernet failure with Ubuntu: PCL issue

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Den
Posts: 3
Joined: Fri Aug 27, 2010 2:30 pm

[SOLVED] Persistent Ethernet failure with Ubuntu: PCL issue

Post by Den »

Hi all,

I had a working distro of Kubuntu 9.04 on my fit-pc2 until last week, then I decided to make a clean install of (K)Ubuntu 9.10. Since then, I'm living a true nightmare as every distro I install (8.10, 9.04, 9.10, even 10.04) from a USB Key has huge networking issues (on Ethernet, didn't check the WLAN).

Here's a quick description of my problem:
* sometimes the network seems ok for a few minutes, then it becomes totally unresponsive (no ping to other computers, no http (wget, firefox, Konqueror, apt...)
* sometimes the network doesn't start at all since the boot.
* even when booted on the USB dongle, I can't sometimes reach the network
BUT it always gets the correct IP from the router (I recorded its MAC address on the router so it would always get a certain IP)

I know there are many problems involving Internet connections in Ubuntu but everything I tried from the literature was in vain (disabling ipv6, changing the MTU, trying DHCP with manual DNS entries, ...). No luck.

My last try (of maybe a dozen of them...) was with Kubuntu 9.04, following the instructions on the fit-pc2 wiki. Everything looked OK (even VLC with HDTV streaming) until I made

Code: Select all

sudo apt-get upgrade
and rebooted. After that, no connexion, still the correct IP but no ping to to/from other computers on the network.

I also tried disabling Hyperthreading (though I don't think it could be the cause of the issue here) but nothing changed.

To be more precise it's linked to a 100MB/1GB ADSL Router (Optical Freebox v5 for the french guys here) via a Powerline Communications plug, and this router is the only "new" thing since my resintall frenzy.

Intermittent failures are the worst by far, and I'm beginning to feel really pessimistic about this one.
Do you see something else I could try or do I definitely blame it on faulty hardware :) ?

__
Denis
Last edited by Den on Sat Aug 28, 2010 6:37 pm, edited 1 time in total.

fly
Posts: 162
Joined: Thu Jul 22, 2010 2:02 pm

Re: Persistent Ethernet failure with Linux (Ubuntu)

Post by fly »

Well, that sounds really weird...
* sometimes the network seems ok for a few minutes, then it becomes totally unresponsive (no ping to other computers, no http (wget, firefox, Konqueror, apt...)
The drivers for RTL8111/8168B ethernet chip have had some problems detecting the prober card, which lead to a behavior where the network went down after some packets send. There are quite some information on that issue in the ubuntu launchpad bugtracker, e.g. [1]. In an up-to-date 10.04 this should have been fixed; it is fixed in the repository from compulab for all versions they support. You can compile the driver by yourself which will fix this problem regardless of your installed version. However, I don't recommend this. Here is a snippet from my writeup done in January for SLAX - you might need to update it for Ubuntu:
# Frist get driver from [2]!
$ ifconfig eth0 down
$ rmmod r8169
$ rmmod r8168
$ echo "blacklist r8169" >> /etc/modprobe.d/blacklist
$ tar xvjf r8168*
$ cd r8168*
$ make clean modules
$ make install
$ depmod -a
$ modprobe r8168
$ ifconfig eth0 up
$ dhcpcd eth0
* sometimes the network doesn't start at all since the boot.
What do you mean? There are some reports on NICs disappearing completly from the pci line. Turning off, remove power supply, reattach power, boot up and look if its up again. More information are available right on this board here, e.g. this thread [3].
* even when booted on the USB dongle, I can't sometimes reach the network
This should be related to the first bug.

[1] https://bugs.launchpad.net/ubuntu/+sour ... bug/221499
[2] http://www.realtek.com.tw/products/prod ... l=5&Conn=4
[3] http://www.fit-pc2.com/forum/viewtopic.php?f=51&t=1858

Den
Posts: 3
Joined: Fri Aug 27, 2010 2:30 pm

Re: Persistent Ethernet failure with Linux (Ubuntu)

Post by Den »

Hi Fly,

Thanks for the thorough reply.
What do you mean? There are some reports on NICs disappearing completly from the pci line. Turning off, remove power supply, reattach power, boot up and look if its up again. More information are available right on this board here, e.g. this thread [3].
Sorry, I was not very precise in the description; when I say that the network doesn't start I mean I can't get any packet on any port once I'm logged and try different things (such as ping, wget, etc); but the fit-pc2 still gets (and displays) a correct IP given by the router.
Also, sometimes (like this morning) after booting/logging I get a connexion but a painfully slow one (like 1 ko/s...); I think it should be categorized as another trouble, but still.

I'll follow your advice and recompile the driver, thanks. My only doubt is, if the driver isn't compatible, it shouldn't even negotiate the connexion with the router, I think?
Answer in a couple of hours...

By the way, two more thoughts:
* could it be a problem of incompatibility with Gigabit LAN? How do you deactivate gigabit? I saw a "Gigabit LAN" option in the BIOS but I think it basically sets the Ethernet chip on/off, right ?
* about the BIOS, I'm currently configured with "hyperthreading disabled", and "GV3 only". I think it should stay so for the time being?

__
Den

Den
Posts: 3
Joined: Fri Aug 27, 2010 2:30 pm

Re: Persistent Ethernet failure with Linux (Ubuntu)

Post by Den »

Hum...

Actually I found out that the responsible was the PLC plug linked to the Eternet port... Sorry I didn't think about it sooner, but as it was brand new and as my first attempts were a great success (>3 Mb/s at the first boot of 9.10) I assumed it was ok.

the problem is: this pair of PCL plugs are actually made by the ISP who provides a pack (ADSL router, PCL plugs, HDTV box, etc...) but they seem to lack compatibility with common networking protocols, as they are initially designed to plug a HDTV box to the router... I don't know if I'm clear (or right, BTW). I don't know if it can be of any help to other users but I began to have some doubts after these two hints:
* at some point, tcp-using protocols had a baudrate about 1ko/s whereas videolan could display HDTV (via udp-streaming) without a glitch... (does that make any sense?)
* no connexion either when I replaced the fit-pc2 with another computer (ok, ok, I could have thought about it sooner, really :oops: )

For the french guys with the same ISP (Free) here: beware if you try to plug your FreePlug into your fit-pc2!

I don't want to use wifi on the long term so I'll buy new, standard PCL plugs, but for the moment I'll go on with the install using WLAN.

Thanks a lot fly, I appreciated your fast answer!

__
Denis

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