From: Krzysztof Halasa <khc@pm.waw.pl>
To: dsaxena@plexity.net
Cc: linux-kernel@vger.kernel.org
Subject: Re: dma_is_consistent() is nonsensical...
Date: Thu, 17 Nov 2005 20:52:02 +0100 [thread overview]
Message-ID: <m3ek5frr19.fsf@defiant.localdomain> (raw)
In-Reply-To: <20051117184745.GA23776@plexity.net> (Deepak Saxena's message of "Thu, 17 Nov 2005 10:47:45 -0800")
Deepak Saxena <dsaxena@plexity.net> writes:
> Working on adding support for cache-coherent operation to ARM and
> wondering exactly what this API is supposed to do. From the name it
> is obviously supposed to tell the caller (only one in the kernel...
> drivers/scsi/53c700.c) whether the provided dma_handle is cache-coherent
> or not. In the case of multiple DMA domains where certain devices
> are on snooping interfaces and others are not we really want to know what
> device the DMA address is on so can we add a struct device* ptr to this
> function? Or can we just kill it since nobody is actually using it?
> Calling dma_alloc_coherent should always return coherent/consistent
> (why the different naming conventions too?) so I don't really see a real
> use case.
I would have to look at the current code but yes, there were issues
like that in the past. Coherent vs consistent - there are two APIs
(DMA and PCI) each with a different name for this.
--
Krzysztof Halasa
prev parent reply other threads:[~2005-11-17 19:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-17 18:47 Deepak Saxena
2005-11-17 19:52 ` Krzysztof Halasa [this message]
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