[ewg] Re: [PATCH 2/14] nes: device structures and defines

[Michael Buesch]

On Wednesday 08 August 2007 18:59:08 Jeff Garzik wrote:
> Michael Buesch wrote:
> > writel doesn't guarantee flushing either.
> > readl does.
> 
> 
> Not quite -- there are multiple kinds of flushing.  You're thinking 
> about flushing across PCI bridges, which is correct, but you also have 
> CPU write posting and CPU write ordering and such.
> 
> Without taking all that into account, you might be tempted to think that 
> __raw_readl() will perform all flushes necessary following a 
> __raw_writel() -- but that would be incorrect.

So, kind of...
Better use writel(swab32(...
unless you like being shot into the foot.

-- 
Greetings Michael.