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Most of the time my network cable is not detected in Ubuntu.

my system config

mercury motherboard via inbuilt ethernetcard

ifconfig result

lo     Link encap:Local Loopback
       inet addr:120.0.0.1 Mask:255.0.0.0
       inet6 addr: ::1/128 Scope:Host
       UP LOOPBACK RUNNING MTU:16436 Metric:1
       RX packets:12 errors:0 dropped:0 overruns:0 frame:0   
       TX packets:12 errors:0 dropped:0 overruns:0 carrier:0 
       collisions:0 txqueuelen:0
       RX bites:720 (720.0 B)  TX bites:720(720.0 B)

lspci result while not working

00:00.0 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.1 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.2 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.3 Host bridge: VIA Technologies, Inc. PT890 Host Bridge
00:00.4 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.7 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237/VX700 PCI Bridge
00:0f.0 IDE interface: VIA Technologies, Inc. VIA VT6420 SATA RAID Controller (rev 80)
00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800/K8T890 South]
00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 60)
01:00.0 VGA compatible controller: VIA Technologies, Inc. CN700/P4M800 Pro/P4M800 CE/VN800 [S3 UniChrome Pro] (rev 01)

In Working condition

00:00.0 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.1 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.2 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.3 Host bridge: VIA Technologies, Inc. PT890 Host Bridge
00:00.4 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.7 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237/VX700 PCI Bridge
00:0f.0 IDE interface: VIA Technologies, Inc. VIA VT6420 SATA RAID Controller (rev 80)
00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800/K8T890 South]
00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 60)
00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II] (rev 78)
01:00.0 VGA compatible controller: VIA Technologies, Inc. CN700/P4M800 Pro/P4M800 CE/VN800 [S3 UniChrome Pro] (rev 01)

How can I fix this?

share|improve this question
    
Please paste a "ifconfig -a" output to your question. Open a terminal, type: "ifconfig -a >> ~/ifconfig.txt" and copy stuff from the ifconfig.txt in your home folder. –  Shiki Apr 17 '11 at 6:48
    
please check my update with ifconfig –  gowri Apr 17 '11 at 7:16
1  
Have you tested your ethernet cable? Maybe it's gone bad... –  tjameson Apr 17 '11 at 8:28
1  
What are you connecting to? Direct to another computer, to a router, to a switch or hub, what? –  Majenko Apr 17 '11 at 9:23
2  
and how come lo is set to 120.0.0.1 ? –  Majenko Apr 17 '11 at 9:24

4 Answers 4

up vote 3 down vote accepted
+25

If the lspci does not show your ethernet card that means you do not have ethernet card. a- This may be a BIOS problem. Bios may disable inbuilt ethernet interface b- This is a hardware issue. Your motherboard need service or replacement.

I think, This is not a driver, cable or operating system issue. My vote is for the choice "b", hardware problem.

share|improve this answer
    
Agreed. I've seen a problem like this before and it solved by replacing the motherboard. –  Heath May 4 '11 at 16:50
    
Yup it should show up with lspci even without any drivers. My brothers motherboard had the same issue. We put in a spare network card and disabled the on-board one in the bios. –  James T May 5 '11 at 0:13

I would say its the driver module, try to check if its loaded:

lsmod | grep via-rhine

If you get nothing, that means the module is not loaded, then you should load it with:

modprobe via-rhine

If you can see the module loaded, try remove it and reload it:

modeprobe -r via-rhine
modeprobe via-rhine 

there is also a known bug about this.

share|improve this answer

Since you say you had the same problem on two computers (with the same motherboard, presumably), that indicates there's probably an incompatibility between that motherboard and the linux pci driver.

Here's something you can try: add pci=nocrs to the kernel command line. You can do this when booting by pressing 'c' on the GRUB screen, or edit the file /etc/default/grub and add pci=nocrs to GRUB_CMDLINE_LINUX_DEFAULT so it looks like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=nocrs"

Be sure to run update-grub before you reboot.

share|improve this answer

This looks to be a hardware problem or a race condition in the driver.

If you can obtain a cheap network card (PCI, PC Card, PCIe) and disable the on-board one in the BIOS.

share|improve this answer
    
No idea what a race condition is, but putting in a network card and disabling the on-board one is a great idea. –  James T May 5 '11 at 0:16
    
Race condition: two things are trying to affect the system at the same time, and it's a race to see which one wins. One of the common symptoms is that the problem is intermittent. –  Broam May 6 '11 at 14:25

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