In Table 22 of the DFI 5.0 specification, the signals dfi_lp_ctrl_wakeup and dfi_lp_data_wakeup are defined as 4-bits wide. However, they appear to have a coding that would imply they should now be 6-bits wide.
The previous dfilp_version=1 encoding only required 4-bits and the signal was 4-bits wide in the older specifications. However, the new dfilp_version=0 encoding requires 5-bits and defines that the 6th bit is 0.
Therefore, I assume that the width of these signals should now be 6-bits but that this was not updated in the specification.
You are correct, the width of the signal depends on the mode supported; for dfilp_version=0, or if both modes supported, the width should be 6 bits. If only dfilp_version=1 is supported, the width can be 4 bits.
I will make a note to fix this in the next version.
Thank you for the clarification.