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From: Michael Ellerman <mpe@ellerman.id.au>
To: Alexander Fomichev <fomichev.ru@gmail.com>,
	linuxppc-dev@lists.ozlabs.org
Cc: Christoph Hellwig <hch@lst.de>, linux@yadro.com
Subject: Re: [RFC PATCH] powerpc: fix get_arch_dma_ops() for NTB devices
Date: Wed, 30 Jan 2019 23:58:40 +1100	[thread overview]
Message-ID: <87imy6pain.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20190128133203.mon4a3nkrzijn43g@alfbook-pro.local>

Alexander Fomichev <fomichev.ru@gmail.com> writes:

> 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.

What's an NTB device?

drivers/ntb I assume?

So it's a PCI device of some sort, but presumably the device you're
calling dma_set_mask() on is an NTB device not a PCI device?

But then it works if you tell it to use the PCI DMA ops?

At the very least the code should be checking for the NTB bus type and
only returning the PCI ops in that specific case, not for all devices.

cheers

  reply	other threads:[~2019-01-30 13:00 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 [this message]
2019-02-04  8:17   ` Christoph Hellwig
2019-02-05 11:20     ` Michael Ellerman
2019-02-05 16:13       ` Christoph Hellwig

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