RTAI kernel disconnects Internet

I have a new install using a Gigabyte motherboard GA-F2A68HM-DS2H which has onboard LAN calling out the Realtek RTL8111/8168B PCI express Gigabit Ethernet Controller. Anytime I install the RTAI kernel the LAN is disconnected. I can Install Ubuntu with the 4.2.0 kernel and internet works fine. If I reconfigure Ubuntu 14.04 with the 3.4-9-rtai-686-pae kernel, the internet is disconnected. I have perform a lspci -v on both configurations and everything looks the same except for the IRQ interrupt value, one is 32 and the other is 31. I found on the internet claims that the Ethernet controller does not like the r8169 kernel driver, but I replaced it with the r8168 which supposedly works better but no change.

I have two version of Ubuntu I can boot into, one using the config-4.2.0-34-generic kernel and one using the 3.4-9-rtai-686-pae kernel, and of course, the first one works the lan and the second does not. On these installs, would the only difference be the contents of the kernel file, or are there other files involved in the install that could be different? If the difference is simply the kernel files then I can start swapping out sections from one to the other until I identify what is making the LAN disconnect. This may not be a pretty solution, but in time it should work.

Any suggestion on how to solve this type of problem?

I can't help with the cause of your problem but my system, an old HP DX2710, also has the Realtek controller and has no problems. Controller is:
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)

The kernel running is 3.4-9-rtai-686-pae under Debian Wheezy with Linuxcnc 2.7.3.

Sir:

I have exactly the same problem.
I have been researching it and it appears that the rtai is missing a module (driver)
"alx" . The version that is running has this when you use lsmod and rtai doesn't.
I am trying to figure out how to install it.

Maybe someone else who understands modules could help??
or maybe it is crazy.

Fayette

Pretty sure that the atx driver is for a Qualcomm network card, not Realtek. It certainly isn't present in my kernel.

That sounds promising. If this is the module that is missing, then according to a linux friend, all you need to do is go into terminal mod (type cntrl alt t) and then type "insmod (filename)" which will insert the listed module into the kernel. You may need to use "sudo insmod (filename)" which will run the insmod command with system (root) privilege. I am still working at comparing Ubuntu 14.04 with the generic kernel (where the lan works) to Ubuntu 14.04 with the rtai kernel (where the lan does not work) to identify which module is missing on my machine. I will look to see if alx is the module that is causing my problem and let you know the results. I also found out that I lose my touchscreen when I switch from the generic to the rtai kernel so I need to see if I am also missing a module for that.

Can you do an 'lsmod' command with and without the realtime modules loaded and post the results here?

Have you installed firmware-realtek ?

packages.debian.org/wheezy/firmware-realtek

Also firmware-linux and firmware-linux-nonfree

You may need to install the later version of firmware-realtek from wheezy-backports or Jessie if you get messages saying there is further firmware required.

It is nothing to do with the kernel, because the hardware uses modules, just presumably that you don't have them installed in /lib/modules for that kernel and your initrd.img was not built when they were in the system.

If you do lspci -k, you should get a print showing what module is in use for your NIC, eg

If you look in /lib/modules/3.4.9-rtai/modules.dep
you should find a line similar to

dmesg | grep 'eth0' should also show you kernel messages to see what is happening at boot with the NIC

eg
regards

I solved my problems completely. First off you need to understand that a lot of these versions of Linux are really old and the reason they are not supporting these lan cards or my touchscreens is because the kernels are older than the components. These builds work fine if you are using an old PC that you found in the garage, but if you go out and get new hardware then you may have problems.

I got new hardware consisting of the following:
1) Gigabyte GA-F2A68HM-DS2H motherboard which has onboard lan ($49.99 from Frys - don't go there horrible service)
2) AMD FM2+ 7650K quad core processor ($102.88 also from Frys, again don't go there, still horrible service)
3) Corsair Vengeance DDR3 8GB 1600MH (2x4gb) memory ($59.99 from Frys, absolutely don't go there, horrible service)
4) WD 500Gb SATA drive (extra drive in closet) (free)
4)Microsoft ergonomic keyboard (alright, this came from the garage) (free)
5)Logitech trakball (also a garage item) (free)
6) ACER T232HL touchscreen LCD monitor ($311 from staples with coupon)

The two problem areas I had were the onboard lan and the touchscreen working whenever I tried the iso distributions using the older rtai kernels. The problem is not the kernel itself, but the underlying Ubuntu 10.xx or the Debian Wheasy, which are both old builds. Understand that Ubuntu 10.04.xx was built in April 2010, that is why the 10.04 in the name.

To fix my problem, I chose to load a newer version of Ubuntu 14.04 (64 Bit version) and then insert a newer version of the rtai kernel into the system. I chose Ubuntu 14.04 as my base system because when I initially loaded Ubuntu 14.04 all my hardware worked which meant that Ubuntu 14.04 had all the drivers( i..e. linux modules) to support my hardware. I followed the instructions contained in the attached file on how to take my Ubuntu 14.04 build with the generic kernel and rebuild it with the rtai kernel. The rebuild used the 3.10.32 version of the rtai kernel. The goal was to use the basic Ubuntu 14.04 system which has all the drivers (i.e. modules) that would run my hardware, and while keeping those good qualities, insert the rtai kernel so the result would have the realtime capability necessary for linuxcnc. I have not yet verified that linuxcnc will run on this kernel.

The rebuild instructions where fairly good, but in a couple of places they assumed I was smarter than I really am, so I had to figure out why some commands did not work. I added my own comments into the instructions where there were things I did not know. I have completed the instructions to the point where I rebooted my system and I have Ubuntu 14.04 running with the 3.10.32-rtai kernel and all my hardware works. I did loose the higher resolution on my monitor, but I would guess that is a simple fix once I figure out where to set the screen resolution. The one problem I was hoping to avoid was if somehow my hardware conflicted with the rtai kernel, then I would be screwed. Luckily no conflicts occurred and it seems my main problems were simply that the older system versions did not have the right drivers (i.e. modules) to support my hardware.

I am going to be interrupted by other work so it will be a week or so before I can work the next step of figuring out how to load linuxcnc onto this system and see if it will work with the 3.10.32-rtai kernel.

The driver I think people are missing for their lan is the R8169. When I load earlier rtai versions the driver that was listed was the r6168 on my system. I fixed all my problems by loading ubuntu 14.04 (which had all my drivers working) and then rebuilt it with the 3.10.32 rtai kernel. I still have not figured out if linuxcnc will work with the 3.10.24 rtai kernel, but I think I am making progress.