From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
Paul Burton <paul.burton@mips.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mips@linux-mips.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/6] dma-mapping: merge direct and noncoherent ops
Date: Wed, 31 Oct 2018 14:24:13 +0000 (GMT) [thread overview]
Message-ID: <alpine.LFD.2.21.1810311414200.20378@eddie.linux-mips.org> (raw)
In-Reply-To: <20180914095808.22202-5-hch@lst.de>
Hi Christoph,
On Fri, 14 Sep 2018, Christoph Hellwig wrote:
> All the cache maintainance is already stubbed out when not enabled,
> but merging the two allows us to nicely handle the case where
> cache maintainance is required for some devices, but not others.
FYI, you commit bc3ec75de545 ("dma-mapping: merge direct and noncoherent
ops") has caused:
fddi0: DMA command request failed!
fddi0: Adapter open failed!
with the `defxx' driver on my R4400SC TURBOchannel DECstation (but not the
R3400 one) and consequently the interface does not work anymore. Both are
non-coherent cache systems, however the R3400 implements the write-through
policy while the policy of the R4400SC is write-back (it also has 1MiB of
secondary cache), which I suspect is the reason of the difference.
I'll be experimenting with this commit to figure out what the real cause
is, but it'll take a while as my resources are limited, so I'm sending
this early heads-up in case you or someone else has an idea what might be
going wrong here.
Maciej
next prev parent reply other threads:[~2018-10-31 14:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-14 9:58 merge dma_direct_ops and dma_noncoherent_ops v3 Christoph Hellwig
2018-09-14 9:58 ` [PATCH 1/6] dma-mapping: add the missing ARCH_HAS_SYNC_DMA_FOR_CPU_ALL declaration Christoph Hellwig
2018-09-14 9:58 ` [PATCH 2/6] MIPS: don't select DMA_MAYBE_COHERENT from DMA_PERDEV_COHERENT Christoph Hellwig
2018-09-14 9:58 ` [PATCH 3/6] dma-mapping: move the dma_coherent flag to struct device Christoph Hellwig
2018-09-14 9:58 ` [PATCH 4/6] dma-mapping: merge direct and noncoherent ops Christoph Hellwig
2018-10-31 14:24 ` Maciej W. Rozycki [this message]
2018-10-31 16:31 ` Maciej W. Rozycki
2018-10-31 20:32 ` Christoph Hellwig
2018-10-31 20:50 ` Maciej W. Rozycki
2018-11-01 5:13 ` Christoph Hellwig
2018-11-01 7:54 ` [PATCH] MIPS: Fix `dma_alloc_coherent' returning a non-coherent allocation Maciej W. Rozycki
2018-11-01 8:33 ` Christoph Hellwig
2018-11-01 14:30 ` Maciej W. Rozycki
2018-11-05 18:10 ` Paul Burton
2018-09-14 9:58 ` [PATCH 5/6] dma-mapping: consolidate the dma mmap implementations Christoph Hellwig
2018-09-14 9:58 ` [PATCH 6/6] dma-mapping: support non-coherent devices in dma_common_get_sgtable Christoph Hellwig
2018-09-20 7:02 ` merge dma_direct_ops and dma_noncoherent_ops v3 Christoph Hellwig
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