From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Date: Tue, 27 May 2008 12:15:40 +1000 > Some of them. USB comes to mind. I'd be happy to make it "the rule" and > document that MMIO vs. coherent access aren't implicitely ordered. I > would still keep them ordered on powerpc for a little while tho until > I'm happy enough with driver auditing. > > But heh, it's you who was telling me that it would be a bad engineering > decision and we had to make everybody look like x86 & fully ordered :-) > I decided to agree back then and stuck all those nasty heavy barriers > in the powerpc variants of readl/writel/... I still believe this. It's just another complicated thing for driver authors to get wrong. The other side of the coin is of course the cost. The only thing I am absolutely sure of is that we should make a decision fast, document it, and just stick to it. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
