How to avoid the depth texture update when open the shadow?

Unity Engine
1

When turn on the shadow, it always render a depth texture, even there is no post effect or defer lighting.
If there is just turn on the shadow, we can calculate the shadow in the same pass the receive object render.
The current shadow is too much waste when I do not need defer lighting and complex post effect that need depth texture. And this is typic situation on mobile platform.

2

If you say mobile platform, to which platform do you refer in particular? As far as I remember, Unity does do a separate depth pass in the editor, but it won’t when running on an iOS/Metal device.

3

I don’t know the different about the editor and player. I thought the render path is the same.
Is there any document about the depth pass on different platform?