Comment 28 for bug 19711

I don't think the chip should do that much bust mastering activity that it would
prevent entering C3 when doing normal almost idle desktop drawing... I suspect
we might be hitting yet another issue here where the chip gets something wrong
with the memory map and thus keeps trying to hit the bus instead of vram or AGP...

(That would explain why we still have lockups every now and then on some
chipsets... random bus mastering is bad !)

Now of only somebody with a PCI analyzer could get us some traces...