The child Samuel ministered to Yahweh before Eli. The word of Yahweh was precious in those days; there was no frequent vision.
The extreme weakness of such a comment lies in the fact that nothing whatever is said of "centuries" in the first prophecy, and nothing whatever is said in the prophecy here that could be construed as a denial that the prophecy was any different from the previous one.  It is specifically stated that the punishment would last "forever," and also, the sign given to Eli that both his evil sons would die by the sword on the same day (in the first prophecy) indicates the same immediacy and impending nature of God's punishment that exists in the prophecy here.  There is absolutely no discrepancy whatever in these two prophecies.  Thus,  1 Samuel 3:12, as a reference to the previous one, is an established fact.