From: Will Deacon <will.deacon@arm.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Dmitry Osipenko <digetx@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Mikko Perttunen <cyndis@kapsi.fi>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Ben Skeggs <bskeggs@redhat.com>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Nicolas Chauvet <kwizart@gmail.com>,
devicetree@vger.kernel.org, nouveau@lists.freedesktop.org,
iommu@lists.linux-foundation.org,
dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU
Date: Fri, 27 Jul 2018 10:03:28 +0100 [thread overview]
Message-ID: <20180727090328.GH28088@arm.com> (raw)
In-Reply-To: <20180727082512.lpvmeuvxnw3mpeym@8bytes.org>
On Fri, Jul 27, 2018 at 10:25:13AM +0200, Joerg Roedel wrote:
> On Fri, Jul 27, 2018 at 02:16:18AM +0300, Dmitry Osipenko wrote:
> > The proposed solution adds a new option to the base device driver
> > structure that allows device drivers to explicitly convey to the drivers
> > core that the implicit IOMMU backing for devices must not happen.
>
> Why is IOMMU mapping a problem for the Tegra GPU driver?
>
> If we add something like this then it should not be the choice of the
> device driver, but of the user and/or the firmware.
Agreed, and it would still need somebody to configure an identity domain so
that transactions aren't aborted immediately. We currently allow the
identity domain to be used by default via a command-line option, so I guess
we'd need a way for firmware to request that on a per-device basis.
Will
next prev parent reply other threads:[~2018-07-27 9:03 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-26 23:16 [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU Dmitry Osipenko
2018-07-26 23:16 ` Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 1/6] driver core: Add option for disabling of backing devices DMA " Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 5/6] drm/nouveau: tegra: Universally avoid implicit DMA backing " Dmitry Osipenko
[not found] ` <20180726231624.21084-1-digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-07-26 23:16 ` [RFC PATCH v1 2/6] of/device: Don't back devices DMA with IOMMU if that's undesired by driver Dmitry Osipenko
2018-07-26 23:16 ` Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 3/6] drm/tegra: Avoid implicit DMA backing with IOMMU Dmitry Osipenko
2018-07-26 23:16 ` Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 4/6] gpu: host1x: " Dmitry Osipenko
2018-07-26 23:16 ` Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 6/6] Revert "drm/nouveau: tegra: Detach from ARM DMA/IOMMU mapping" Dmitry Osipenko
2018-07-26 23:16 ` Dmitry Osipenko
2018-07-27 8:25 ` [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU Joerg Roedel
2018-07-27 9:03 ` Will Deacon [this message]
[not found] ` <20180727090328.GH28088-5wv7dgnIgG8@public.gmane.org>
2018-07-27 14:10 ` Dmitry Osipenko
2018-07-27 14:10 ` Dmitry Osipenko
2018-07-27 14:20 ` Joerg Roedel
2018-07-27 14:20 ` Joerg Roedel
2018-07-27 17:13 ` Rob Herring
2018-07-27 17:13 ` Rob Herring
2018-07-27 18:31 ` Joerg Roedel
2018-07-27 18:31 ` Joerg Roedel
[not found] ` <20180727183134.GD6738-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2018-07-27 20:02 ` Dmitry Osipenko
2018-07-27 20:02 ` Dmitry Osipenko
2018-07-27 16:02 ` Robin Murphy
2018-07-27 16:02 ` Robin Murphy
[not found] ` <daadd395-dcb7-9505-f171-0fcc28570301-5wv7dgnIgG8@public.gmane.org>
2018-07-27 17:03 ` Jordan Crouse
2018-07-27 17:03 ` Jordan Crouse
[not found] ` <20180727170326.GA21283-9PYrDHPZ2Orvke4nUoYGnHL1okKdlPRT@public.gmane.org>
2018-07-27 17:16 ` Dmitry Osipenko
2018-07-27 17:16 ` Dmitry Osipenko
2018-07-28 11:40 ` Dmitry Osipenko
2018-07-28 11:40 ` Dmitry Osipenko
2018-08-02 18:24 ` Dmitry Osipenko
2018-08-02 18:24 ` Dmitry Osipenko
2018-08-03 15:43 ` Robin Murphy
2018-08-03 17:00 ` Jordan Crouse
2018-08-03 17:00 ` Jordan Crouse
2018-08-15 19:56 ` Dmitry Osipenko
2018-08-16 17:23 ` Robin Murphy
2018-08-16 17:23 ` Robin Murphy
[not found] ` <afecce46-96d2-9688-30b4-0a3f17a651d3-5wv7dgnIgG8@public.gmane.org>
2018-09-20 17:09 ` Dmitry Osipenko
2018-09-20 17:09 ` Dmitry Osipenko
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