So, finaly I found the solution here :
https://bugzilla.redhat.com/show_bug.cgi?id=2220888
Vitezslav Zivota 2023-07-12 08:58:17 UTC
Latest working version is amd-gpu-firmware-20230515-150.fc38.noarch.rpm which you can download from linux-firmware-20230515-150.fc38 | Build Info | koji, this fixes the “Error waiting for DMUB idle”.
Do not forget to regenerate initramfs (dracut --regenerate-all --force) after firmware downgrade.
So I Do :
$ sudo rpm -Uvh --oldpackage amd-gpu-firmware-20230515-150.fc38.noarch.rpm
$ sudo dracut --regenerate-all --force
All is work now, with kernel 6.3.12-200.
And if you want hold the update this package (amd-gpu-firmware) see Fedore section in : https://www.baeldung.com/linux/prevent-specific-package-update.