EFI runtime services are not available when booting RT kernel,
causing applications that depend on EFI variables to fail.

Steps to reproduce:
1. Boot RT kernel
2. Check: ls /sys/firmware/efi/efivars/
3. Result: Empty

Expected: EFI variables should be accessible like in non-RT kernel

Additional info:
- Non-RT kernel works fine
- CONFIG_EFIVAR_FS=m in both kernels
- CONFIG_EFI_DISABLE_RUNTIME is not set in RT kernel
- Same hardware, different behavior

When comparing

grep -E "CONFIG_EFI*" /boot/config-6.12.38+deb13-rt-amd64

against to

grep -E "CONFIG_EFI*" /boot/config-6.12.38+deb13-amd64

The result is,

debian13:~$ diff config-efi-rt.txt config-efi-no-rt.txt
21c21
< CONFIG_EFI_DISABLE_RUNTIME=y
---

Conclusion, On RT kernels seems that CONFIG_EFI_DISABLE_RUNTIME is not set.

Control: reassign -1 src:linux
Control: forcemerge 956752 -1

This should be the same as #956752 . There is a documented workaround
which you can try in https://bugs.debian.org/1021245#10 .

Regards,
Salvatore