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From: Christoph Hellwig <hch@lst.de>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>,
	Alexander Fomichev <fomichev.ru@gmail.com>,
	linux@yadro.com
Subject: Re: [RFC PATCH] powerpc: fix get_arch_dma_ops() for NTB devices
Date: Tue, 5 Feb 2019 17:13:00 +0100	[thread overview]
Message-ID: <20190205161300.GB782@lst.de> (raw)
In-Reply-To: <87h8dimqgv.fsf@concordia.ellerman.id.au>

On Tue, Feb 05, 2019 at 10:20:32PM +1100, Michael Ellerman wrote:
> get_dma_ops() falls into arch-dependant get_arch_dma_ops(), which
> historically returns NULL on PowerPC. Therefore dma_set_mask() fails.
> This affects Switchtec (and probably other) NTB devices, that they fail
> to initialize.
> The proposed patch should fix the issue.

I'm not a fan of this.  powerpc, just like arm64 for example has
required that we set a specific per-device dma ops, which keeps
the assignments clear.  Where do the NTB devices come from?

Might be worth adding the NTB maintainers to the CC list and maybe
linux-iommu.

      reply	other threads:[~2019-02-05 16:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-28 13:32 [RFC PATCH] powerpc: fix get_arch_dma_ops() for NTB devices Alexander Fomichev
2019-01-30 12:58 ` Michael Ellerman
2019-02-04  8:17   ` Christoph Hellwig
2019-02-05 11:20     ` Michael Ellerman
2019-02-05 16:13       ` Christoph Hellwig [this message]

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