This also shouldn’t matter much in this case, but generally you need to do apt purge --auto-remove '*nvidia*' '*nvidia*:i386' '*cuda*' '*cuda*:i386' to really get a clean system.
so it seems it did succeed for non-rt kernel, but not for -rt that you use… Could you please verify this by running find in the non-rt modules folder: find /lib/modules/6.12.57+deb13-amd64 -name '*nvidia*'
If the modules are there, then it will be pretty safe to say that you’ve found a bug in Debian packaging related to -rt kernels and the best course of action is to file one.
In the mean time you can try freshly released Nvidia-packaged DC drivers for d-13:
- purge the Debian packages as described above (this time it does matter to purge it completely)
- download and install https://developer.download.nvidia.com/compute/cuda/repos/debian13/x86_64/cuda-keyring_1.1-1_all.deb : this will install necessary
aptconfigs in/etc/apt/ - you may need to do
apt updateafter that - install the driver with
apt install nvidia-open