Re: [PATCH] Define wc_wmb, a write barrier for PCI write combining

From: Jes Sorensen
Date: Tue Feb 28 2006 - 04:59:08 EST


>>>>> "Bryan" == Bryan O'Sullivan <bos@xxxxxxxxxxxxx> writes:

Bryan> On some platforms, a regular wmb() is not sufficient to
Bryan> guarantee that PCI writes have been flushed to the bus if write
Bryan> combining is in effect.

Bryan> This change introduces a new macro, wc_wmb(), that makes this
Bryan> guarantee.

Bryan,

Could you explain why the current mmiowb() API won't suffice for this?
It seems that this is basically trying to achieve the same thing.

Cheers,
Jes
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