I need to think about that because I don't have a synthesize problem I am working on quartus all the time and only in the end before I am checking my code for real I am going to modelsim for simulation.
The piace of pwm code I wrote does works when it stand by himself
and there was no problem in using the time package then.
More over I am still using it in the main entity because temporlly I have solved the problem by adding another port called duty_cycle tothe pwm component and he his calculated by the same generics...
so I still don't see why it's a problem
I can only agree that "logic has no concept of time"