lkml.org 
[lkml]   [2008]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: MMIO and gcc re-ordering issue
From
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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.


\
 
 \ /
  Last update: 2008-05-27 04:31    [W:0.161 / U:0.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site