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

From: Jeff Garzik <[email-masked]>
Date: Wed, 08 Aug 2007 12:59:08 -0400

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.

	Jeff