Seems to be different takes on what your first post meant, but in addition to my earlier post i'll say this:

IF your problem is you are not getting the flow at the end of the line as you are at the beginning, then 2 things:
1. If you dont have pressure regulating drip line, then go get some and replace what you have.
That will ensure you have the same flow rate at every point along the line.

2. You dont need a lot of pressure or flow rate for drip line.
Tell me what 2 bar and 12l means?

Is bar 2 psi? If not tell me what you have in psi.
Is 12L, gpm? You have 12gpm? If not, then what do you have?