Why is this an issue?

All global resets should be generated within a unique reset management module.

A reset domain is considered as global if:

• It is used in several modules and the ratio of flip-flops using this reset domain is higher than 10%.
• Or it is used in a single module and the ratio of flip-flops using this reset domain is higher than 20%.

A dedicated reset management module brings a lot in terms of reuse and portability. Because all vendor-specific reset elements are generated within the same module, it is easier to replace this module to target other FPGAs.