The democratic mechanism established by Lord Elgin to conciliate the interests of Upper and Lower Canada in the government of the province of Canada was renewed by section 12 of the constitution & reinforced by section 91.
The Governor General chooses a member of Parliament she believes can command a majority. This leader, in turn, seeks a leader of the other House to conciliate the representative composition of their coalition Cabinet and a political program that both Houses would approve. They submit this program to the Governor General who can then attempt to influence the two leaders to accept changes or additions which she then integrates into her speech from the throne.
If they can’t agree to include certain issues in their program, this doesn’t constitute deadlock. If, for example, the provinces don’t agree that the federal government should regulate a matter, this is their right.
If they can’t agree and can’t agree to disagree, then they must submit the question to the people through a general election on the question.