Is there no way to fix kernel headers for RT kernel 5.18.0-3-rt-amd64?

I have been trying to get my wifi working on my LinuxCNC computer but I keep getting this message:

Error! Your kernel headers for kernel 5.18.0-3-rt-amd64 cannot be found.
Please install the linux-headers-5.18.0-3-rt-amd64 package or use the --kernelsourcedir option to tell DKMS where it's located.

I had an old USB WIFI dongle that I first tried to install. I was getting the above error message. It took forever but I finally got it installed. It is aI don't even know exactly what I did to get it installed but after many tries I ended up having to reinstall the linux-headers-5.18.0-3-rt-amd64 package because I inadvertently uninstalled it. Once I rebooted my WIFI connected. BUT it was barely a connection. The absolute best connection I could achieve was 5 Mbps down and .5 Mbps up. And it was hit an miss. It kept disconnecting and reconnecting randomly from time to time.

With that said I bought a new USB3 dongle with dual antennas hoping it would boost the signal. BUT I cannot get the driver for this one installed at all no matter what I do. I get the same error message above.

I am running this on Linux Mint 21 Xcfe on the following build:
MB: ASUS M5A78L-M/USB3
CPU: AMD FX-6300 Six-core Processor 3.5 GHz
RAM: 8GB DDR3-1600 (800MHz clock) PC3-12800

uname -a:
Linux LinuxCNC 5.18.0-3-rt-amd64 #1 SMP PREEMPT_RT Debian 5.18.14-1 (2022-07-23) x86_64 x86_64 x86_64 GNU/Linux

lsusb:
Realtek Semiconductor Corp. RTL88x2bu [AC1200 Techkey]

I tried the following methods (and a couple similar ones):
AND
I installed the generic headers (code below) as a test to see if the Realtek USB WIFI Dongle worked and the results were outstanding. I am getting 170 Mbps down and 12 Mbps up.
Since my CNC is out in my shop and there is no wired ethernet available out there WIFI is my best option.

Obviously the dongle works great in Linux Mint. Why is it not possible to get it to work with the RT kernel? Or does anyone know how to get it working (with decent speeds)? 5 Mbps is not workable. I would be happy with 20+ Mbps.

My question is, what is wrong with the kernel headers? Why are they not found? Seems like the build was not completed correctly or something. I wonder if this would fix the problem with installing the drivers? Obviously the dongle works great in Linux Mint. Does anyone know how to get it working with the RT kernels (with decent speeds)?

Thanks


 

I did try to install these headers
linux-headers-5.18.0-3-rt-amd64_5.18.14-1_amd64.deb

BUT I kept getting this error message and it would not let me install:
ERROR: Dependency is not satisfiable: linux-headers-5.18.0-3-common-rt (= 5.18.14-1)

Are these the correct headers?
 

Go back to Debian Bookworm nonfree. 
The RTL88x2bu driver is very buggy. If bookworm does not support it, Maybe try this
github.com/RinCat/RTL88x2BU-Linux-Driver
Sometimes I've found the system can get confused about what kernel is running if you've installed preempt_rt as multiple kernels are installed. You can try specific header for your kernel like this.sudo apt install -y linux-headers-$(uname -r)

Once I figured out how to get the WIFI working I was going to do a fresh install since I have been messing with drivers and kernels. I will give Debian a try.

Is Debian 11.4 non-free the latest version?

Thanks guys!

Debian 12 non-free includes linuxcnc natively and will have better support for new hardware in the newer Linux kernel
sudo apt install linuxcnc-uspace
But if its all working, stay where you are.

As I mentioned I plan to start fresh anyway. Plus since messing with all the drivers and kernels my latency on that machine went through the roof. Hopefully a fresh Debian build will get it back down and maybe have support for my usb dongle.

Thanks for the assist!

Hey guys,
Sorry for the dumb question but I am new to Debian. Can someone give me a link to download Debian 12 Bookworm non-free (USB Live)? I cannot find it. OR do I need to install 11.4 and upgrade as JT shows in his instructions?

Not a fan of upgrading if I can install the fresh full version.

From what I can tell I have to upgrade. I will work on it tomorrow.

If I understand it correctly I can just install LinuxCNC from the repo if I have the Mesa 7i76E?

Thanks