multi gpu support?

hello, i complie your code on ubuntu14.04 to finetune the wu's model with scaled_cosine_softmax. your caffe could be compiled successfully.But ,when i go to finetune the model with four nvidia gpu card , it says that it dosen't support multi-gpu.(`caffe train --solver=*** --weights=*** --gpu=0,1,2,3`) .
when i use `(caffe train --solver=*** --weights=*** --gpu=0`,it works.
is this normal?
thank you.