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From: Fredrik Noring <noring@nocrew.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>,
	m.szyprowski@samsung.com, Geoff Levand <geoff@infradead.org>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	JuergenUrban@gmx.de
Subject: Re: [PATCH] dma-mapping: Relax warnings for per-device areas
Date: Tue, 17 Jul 2018 18:33:30 +0200	[thread overview]
Message-ID: <20180717163330.GE2342@localhost.localdomain> (raw)
In-Reply-To: <20180717145725.GA22109@lst.de>

Hi Christoph, Geoff,

[ CC-ing Geoff to give him an opportunity to chime in about the PS3 part. ]

> > Here are three other regressions related to the coherent mask WARN_ON_ONCE:
> 
> They are a pretty strong indication that yes, you should really set
> the coherent mask if you ever do coherent allocations..

I'm unfortunately unfamiliar with the USB drivers for the PS3. Geoff, what
do you think about setting a coherent mask?

Christoph, what mask value would you suggest for the PS2 driver? Typical
DMA addresses 0-0x200000 are mapped to 0x1c000000-0x1c200000 and is memory
managed exclusively by the IOP. Robin indicated that DMA_BIT_MASK(20) or a
nonzero but useless value such as 1 are possibly candidates. It seems quite
unclear what the coherent mask actually means in this case, doesn't it?

Fredrik

  reply	other threads:[~2018-07-17 16:33 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-03 13:08 [PATCH] dma-mapping: Relax warnings for per-device areas Robin Murphy
2018-07-03 16:47 ` Fredrik Noring
2018-07-05 19:36 ` Christoph Hellwig
2018-07-06 11:57   ` Robin Murphy
2018-07-06 14:19     ` Fredrik Noring
2018-07-06 16:46       ` Robin Murphy
2018-07-06 20:54         ` Fredrik Noring
2018-07-06 23:35           ` Aw: " "Jürgen Urban"
2018-07-07  6:32             ` Fredrik Noring
2018-07-08 20:47               ` Aw: " "Jürgen Urban"
2018-07-15 12:28   ` Fredrik Noring
2018-07-17 14:57     ` Christoph Hellwig
2018-07-17 16:33       ` Fredrik Noring [this message]
2018-07-18 21:55         ` Geoff Levand
2018-07-19 13:16           ` Christoph Hellwig

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