From: Thierry Reding <treding@nvidia.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
linux-kernel@vger.kernel.org,
Tobias Jakobi <tjakobi@math.uni-bielefeld.de>,
iommu@lists.linux-foundation.org, Ben Skeggs <bskeggs@redhat.com>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
Date: Mon, 14 Jan 2019 17:09:03 +0100 [thread overview]
Message-ID: <20190114160902.GB9218@ulmo> (raw)
In-Reply-To: <20190114132240.12125-1-m.szyprowski@samsung.com>
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On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote:
> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3.
>
> That patch broke IOMMU support for devices, which fails to probe for the
> first time and use deferred probe approach. When non-NULL dma_ops is set
> in arm_iommu_detach_device(), the given device later ignored by
> arch_setup_dma_ops() and stays with non-IOMMU dma_ops.
>
> Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()"
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> arch/arm/mm/dma-mapping.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
Can you point out exactly what drivers break because of this change? We
need to find a solution that works for everyone. Reverting is only
marginally useful because somebody will just end up wanting to revert
the revert because a different driver is now broken.
Thierry
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next prev parent reply other threads:[~2019-01-14 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190114132250eucas1p2abdf2f36bad3554e37dfbf40e539f594@eucas1p2.samsung.com>
2019-01-14 13:22 ` [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()" Marek Szyprowski
2019-01-14 16:09 ` Thierry Reding [this message]
2019-01-14 16:38 ` Robin Murphy
2019-01-14 20:20 ` Tobias Jakobi
2019-01-15 15:29 ` Thierry Reding
2019-01-16 10:36 ` Marek Szyprowski
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