my 990 is hooked up to my blu ray player using 7.1 analog and dvi. how come to get video picture i must first press 7.1 input on my 990 and then press dvd input on the 990 in order to get both the audio and video?

my 990 7.1 video source is set to dvi 1 which is what the blu ray is connected to so i don't understand why i must press dvd in order to get the picture. if i don't press dvd i only get audio, and besides i thought dvd source does not accept 7.1 analog as an input at all.

what am i missing?