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From: Christoph Hellwig <hch@lst.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: "Robin Murphy" <robin.murphy@arm.com>,
	"Christoph Hellwig" <hch@lst.de>,
	"Horia Geantă" <horia.geanta@nxp.com>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	linux-imx@nxp.com
Subject: Re: [PATCH] swiotlb: sync buffer when mapping FROM_DEVICE
Date: Thu, 23 May 2019 18:43:32 +0200	[thread overview]
Message-ID: <20190523164332.GA22245@lst.de> (raw)
In-Reply-To: <0c79721a-11cb-c945-5626-3d43cc299fe6@samsung.com>

On Thu, May 23, 2019 at 07:35:07AM +0200, Marek Szyprowski wrote:
> Don't we have DMA_BIDIRECTIONAL for such case?

Not sure if it was intended for that case, but it definitively should
do the right thing for swiotlb, and it should also do the right thing
in terms of cache maintainance.

> Maybe we should update 
> documentation a bit to point that DMA_FROM_DEVICE expects the whole 
> buffer to be filled by the device?

Probably. Horia, can you try to use DMA_BIDIRECTIONAL?

  parent reply	other threads:[~2019-05-23 16:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22  7:20 Horia Geantă
2019-05-22 12:32 ` Christoph Hellwig
2019-05-22 12:50   ` Robin Murphy
2019-05-22 13:09     ` Christoph Hellwig
2019-05-22 13:25       ` Robin Murphy
2019-05-22 13:34         ` Christoph Hellwig
2019-05-22 13:55           ` Robin Murphy
2019-05-23  5:35             ` Marek Szyprowski
2019-05-23 16:25               ` Horia Geanta
2019-05-23 16:43               ` Christoph Hellwig [this message]
2019-05-23 17:53                 ` Horia Geanta
2019-05-23 18:05                 ` Robin Murphy

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