Real-time kerel not detected on patched 6.12

It should work indeed when selected fully preempted. At least it worked for me until 6.11 (after patching). What's strange for me is that when it's set manually to rt prio it works

tommylight wrote:

www.phoronix.com/news/Linux-6.12-Does-Real-Time
6.12 does not need patching for AMD64 according to the above, it should work with just setting the preemption to full. That needs to be tested.
 

Not so lucky Tommy. You still need to compile the kernel to get PREEMPT_RT on 6.12 after setting fully preemptible kernel under general settings in menuconfig when compiling the kernel.
But you no longer need to apply the RT patch before compiling the kernel.
There are a few tutorials on this. HEre is one for the Pi 5
github.com/by/RT-Kernel

This is actually quite exciting for Pi users. One of the problems using earlier pi kernel code (eg the rpi-6.1.y  branch used in linuxcnc) was that you had to pull code at a specific commit that matches the RT patch as there was a risk the code deviated too far from the patch and you ended up building a broken kernel. By using the 6.12.y branch head of the Pi kernel, it will always be up to date
Interested users who wanted to compile a complete image for the pi4b or pi5 could clone the linuxcnc rpi-img-builder-lcnc (2.9.3 branch) or the master version in my repo which is arguably more up to date.
github.com/rodw-au/rpi-img-builder-lcnc/tree/linuxcnc-2.9.3
You would need to:
1. delete the RT patch in github.com/rodw-au/rpi-img-builder-lcnc/.../patches/userpatches
2. delete the commit details (2 lines) here github.com/rodw-au/rpi-img-builder-lcnc/...9.3/userdata.txt#L28
3. Change the kernel version here  to 6.12.y github.com/rodw-au/rpi-img-builder-lcnc/....9.3/userdata.txt#L7
 And it should build. (cross compiled on an x86 PC)

Bonus marks if you merge the upstream repo in but that will likely break some of the config files which will need tweaking after recreating.