Texture shading mode problems


I’ve been doing a lot of uv unwrapping recently. And as I’m sure most of you do as well, I like to be able to have my model in texture shading mode so I can see what I’m doing while I’m working. But every now and then the texture shading just plum doesn’t work. It just shows all the faces as black. Except sometimes a few here and there will be white like they should be with no texture applied. I don’t know if this is a bug or just something I’ve turned on/off that I don’t know about. But it’s driving me crazy because the only way to check that my texture is lining up how it should is by rendering it.
So any clues would be appreciated.
Here’s a pic:

thats a bit bizarre :o
are your lights bright enough?

No it doesn’t have anything to do with the lights. Sometimes I’ll use the exact same lighting setup with two different blends and one will be good while the other will be black.