This problem has persisted since ages, perhaps even Mageia 5, but for sure with Mageia 6 and now 7.
If I reboot from the login screen (kdm?), all works fine, the system shuts down, then comes back up.
If I shut down, the system doesn't shut down cleanly, it throws a kernel panic with blinking keyboard lights.
I have managed to narrow things down to the driver "cx8800" of my tv-card. If I unload that module, the system will shut down cleanly.
Unfortunately, I can't unload it after having used it - and if I blacklist it, I can't use my ir remote control anymore, which is a strong conflict of interest. Actually, no, it's not, there's no contest. I need the remote. Shutting down cleanly? I either reboot, or just suspend.
But: it indicates something is wrong with the kernel / module.
Now, where to go from here? Mageia bugreport? Kernel bugreport?