From: Christoph Hellwig <hch@infradead.org>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: "Daniel Vetter" <daniel@ffwll.ch>,
"Christoph Hellwig" <hch@infradead.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Jerome Glisse" <jglisse@redhat.com>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Logan Gunthorpe" <logang@deltatee.com>,
"Christian König" <christian.koenig@amd.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag
Date: Tue, 24 Apr 2018 23:41:18 -0700 [thread overview]
Message-ID: <20180425064118.GA28100@infradead.org> (raw)
In-Reply-To: <CADnq5_P3bT0TStSXpKh11ydifv=KwKtRj-7tDS=GQXey+8tBPw@mail.gmail.com>
On Wed, Apr 25, 2018 at 02:24:36AM -0400, Alex Deucher wrote:
> > It has a non-coherent transaction mode (which the chipset can opt to
> > not implement and still flush), to make sure the AGP horror show
> > doesn't happen again and GPU folks are happy with PCIe. That's at
> > least my understanding from digging around in amd the last time we had
> > coherency issues between intel and amd gpus. GPUs have some bits
> > somewhere (in the pagetables, or in the buffer object description
> > table created by userspace) to control that stuff.
>
> Right. We have a bit in the GPU page table entries that determines
> whether we snoop the CPU's cache or not.
I can see how that works with the GPU on the same SOC or SOC set as the
CPU. But how is that going to work for a GPU that is a plain old PCIe
card? The cache snooping in that case is happening in the PCIe root
complex.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: "moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Christoph Hellwig" <hch@infradead.org>,
"Jerome Glisse" <jglisse@redhat.com>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Logan Gunthorpe" <logang@deltatee.com>,
"Christian König" <christian.koenig@amd.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag
Date: Tue, 24 Apr 2018 23:41:18 -0700 [thread overview]
Message-ID: <20180425064118.GA28100@infradead.org> (raw)
In-Reply-To: <CADnq5_P3bT0TStSXpKh11ydifv=KwKtRj-7tDS=GQXey+8tBPw@mail.gmail.com>
On Wed, Apr 25, 2018 at 02:24:36AM -0400, Alex Deucher wrote:
> > It has a non-coherent transaction mode (which the chipset can opt to
> > not implement and still flush), to make sure the AGP horror show
> > doesn't happen again and GPU folks are happy with PCIe. That's at
> > least my understanding from digging around in amd the last time we had
> > coherency issues between intel and amd gpus. GPUs have some bits
> > somewhere (in the pagetables, or in the buffer object description
> > table created by userspace) to control that stuff.
>
> Right. We have a bit in the GPU page table entries that determines
> whether we snoop the CPU's cache or not.
I can see how that works with the GPU on the same SOC or SOC set as the
CPU. But how is that going to work for a GPU that is a plain old PCIe
card? The cache snooping in that case is happening in the PCIe root
complex.
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next prev parent reply other threads:[~2018-04-25 6:41 UTC|newest]
Thread overview: 161+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-25 10:59 [PATCH 1/8] lib/scatterlist: add sg_set_dma_addr() helper Christian König
2018-03-25 10:59 ` Christian König
2018-03-25 10:59 ` [PATCH 2/8] PCI: Add pci_find_common_upstream_dev() Christian König
2018-03-25 10:59 ` Christian König
2018-03-28 12:38 ` Christoph Hellwig
2018-03-28 15:07 ` Christian König
2018-03-28 15:07 ` Christian König
2018-03-28 15:47 ` Logan Gunthorpe
2018-03-28 16:02 ` Christian König
2018-03-28 16:02 ` Christian König
2018-03-28 16:25 ` Logan Gunthorpe
2018-03-28 18:28 ` Christian König
2018-03-28 18:28 ` Christian König
2018-03-28 18:57 ` Logan Gunthorpe
2018-03-28 19:44 ` Christian König
2018-03-28 19:44 ` Christian König
2018-03-28 19:53 ` Logan Gunthorpe
2018-03-29 11:44 ` Christian König
2018-03-29 15:45 ` Logan Gunthorpe
2018-03-29 16:10 ` Christian König
2018-03-29 16:10 ` Christian König
2018-03-29 16:25 ` Logan Gunthorpe
2018-03-29 18:15 ` Christian König
2018-03-29 18:15 ` Christian König
2018-03-30 1:58 ` Jerome Glisse
2018-03-30 1:58 ` Jerome Glisse
2018-03-30 6:33 ` Christoph Hellwig
2018-03-30 6:33 ` Christoph Hellwig
2018-03-30 15:25 ` Jerome Glisse
2018-03-30 18:46 ` Logan Gunthorpe
2018-03-30 19:45 ` Jerome Glisse
2018-03-30 19:45 ` Jerome Glisse
2018-04-02 17:02 ` Logan Gunthorpe
2018-04-02 17:20 ` Jerome Glisse
2018-04-02 17:20 ` Jerome Glisse
2018-04-02 17:37 ` Logan Gunthorpe
2018-04-02 19:16 ` Jerome Glisse
2018-04-02 19:16 ` Jerome Glisse
2018-04-02 19:32 ` Logan Gunthorpe
2018-04-02 19:45 ` Jerome Glisse
2018-04-02 19:45 ` Jerome Glisse
[not found] ` <CADnq5_P-z=Noos_jaME9_CERri3C-m2hPPvx2bArr36O=1FnrA@mail.gmail.com>
2018-03-29 14:37 ` Alex Deucher
2018-03-29 14:37 ` Alex Deucher
2018-03-25 10:59 ` [PATCH 3/8] PCI: Add pci_peer_traffic_supported() Christian König
2018-03-25 10:59 ` Christian König
2018-03-25 10:59 ` [PATCH 4/8] dma-buf: add peer2peer flag Christian König
2018-03-25 10:59 ` Christian König
2018-03-29 6:57 ` Daniel Vetter
2018-03-29 6:57 ` Daniel Vetter
2018-03-29 11:34 ` Christian König
2018-03-29 11:34 ` Christian König
2018-04-03 9:09 ` Daniel Vetter
2018-04-03 9:09 ` Daniel Vetter
2018-04-03 17:06 ` Jerome Glisse
2018-04-03 17:06 ` Jerome Glisse
2018-04-03 18:08 ` Daniel Vetter
2018-04-03 18:08 ` Daniel Vetter
2018-04-16 12:39 ` Christoph Hellwig
2018-04-16 12:39 ` Christoph Hellwig
2018-04-16 13:38 ` Daniel Vetter
2018-04-16 13:38 ` Daniel Vetter
2018-04-19 8:16 ` Christoph Hellwig
2018-04-19 8:16 ` Christoph Hellwig
2018-04-20 7:13 ` Daniel Vetter
2018-04-20 7:13 ` Daniel Vetter
2018-04-20 8:58 ` Christian König
2018-04-20 8:58 ` Christian König
2018-04-20 10:17 ` Christoph Hellwig
2018-04-20 10:17 ` Christoph Hellwig
2018-04-20 10:44 ` Christian König
2018-04-20 10:44 ` Christian König
2018-04-20 12:46 ` Christoph Hellwig
2018-04-20 15:21 ` [Linaro-mm-sig] " Daniel Vetter
2018-04-24 18:48 ` Christoph Hellwig
2018-04-24 18:48 ` Christoph Hellwig
2018-04-24 19:32 ` Daniel Vetter
2018-04-24 19:32 ` Daniel Vetter
2018-04-25 5:48 ` Christoph Hellwig
2018-04-25 5:48 ` Christoph Hellwig
2018-04-25 6:10 ` Alex Deucher
2018-04-25 6:10 ` Alex Deucher
2018-04-25 6:13 ` Daniel Vetter
2018-04-25 6:13 ` Daniel Vetter
2018-04-25 6:23 ` Daniel Vetter
2018-04-25 6:23 ` Daniel Vetter
2018-04-25 6:43 ` Christoph Hellwig
2018-04-25 6:43 ` Christoph Hellwig
2018-04-25 7:02 ` Daniel Vetter
2018-04-25 7:02 ` Daniel Vetter
2018-04-25 7:09 ` Christoph Hellwig
2018-04-25 7:09 ` Christoph Hellwig
2018-04-25 7:30 ` Daniel Vetter
2018-04-25 7:30 ` Daniel Vetter
2018-04-25 7:56 ` Thierry Reding
2018-04-25 7:56 ` Thierry Reding
2018-04-25 8:55 ` Christoph Hellwig
2018-04-25 8:55 ` Christoph Hellwig
2018-04-25 7:43 ` Thierry Reding
2018-04-25 7:43 ` Thierry Reding
2018-04-25 7:41 ` Thierry Reding
2018-04-25 7:41 ` Thierry Reding
2018-04-25 8:54 ` noveau vs arm dma ops Christoph Hellwig
2018-04-25 8:54 ` Christoph Hellwig
2018-04-25 8:54 ` Christoph Hellwig
2018-04-25 9:25 ` Russell King - ARM Linux
2018-04-25 9:25 ` Russell King - ARM Linux
2018-04-25 10:04 ` Daniel Vetter
2018-04-25 10:04 ` Daniel Vetter
2018-04-25 10:04 ` Daniel Vetter
2018-04-25 15:33 ` Christoph Hellwig
2018-04-25 15:33 ` Christoph Hellwig
2018-04-25 15:33 ` Christoph Hellwig
2018-04-25 21:35 ` Daniel Vetter
2018-04-25 21:35 ` Daniel Vetter
2018-04-25 21:35 ` Daniel Vetter
2018-04-25 23:26 ` Russell King - ARM Linux
2018-04-25 23:26 ` Russell King - ARM Linux
2018-04-26 9:17 ` Daniel Vetter
2018-04-26 9:17 ` Daniel Vetter
2018-04-26 9:17 ` Daniel Vetter
2018-04-26 9:09 ` Christoph Hellwig
2018-04-26 9:09 ` Christoph Hellwig
2018-04-26 9:09 ` Christoph Hellwig
2018-04-26 9:45 ` Daniel Vetter
2018-04-26 9:45 ` Daniel Vetter
2018-04-26 9:45 ` Daniel Vetter
2018-04-26 11:12 ` Russell King - ARM Linux
2018-04-26 11:12 ` Russell King - ARM Linux
2018-04-25 22:54 ` Russell King - ARM Linux
2018-04-25 22:54 ` Russell King - ARM Linux
2018-04-26 9:13 ` Christoph Hellwig
2018-04-26 9:13 ` Christoph Hellwig
2018-04-26 9:13 ` Christoph Hellwig
2018-04-26 9:20 ` [Linaro-mm-sig] " Daniel Vetter
2018-04-26 9:20 ` Daniel Vetter
2018-04-26 9:20 ` Daniel Vetter
2018-04-26 9:24 ` Christoph Hellwig
2018-04-26 9:24 ` Christoph Hellwig
2018-04-26 9:24 ` Christoph Hellwig
2018-04-26 9:39 ` Daniel Vetter
2018-04-26 9:39 ` Daniel Vetter
2018-04-26 9:39 ` Daniel Vetter
2018-04-25 6:24 ` [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag Alex Deucher
2018-04-25 6:24 ` Alex Deucher
2018-04-25 6:41 ` Christoph Hellwig [this message]
2018-04-25 6:41 ` Christoph Hellwig
2018-04-25 17:44 ` Alex Deucher
2018-04-25 17:44 ` Alex Deucher
2018-04-25 18:38 ` Dan Williams
2018-04-25 18:38 ` Dan Williams
2018-05-04 12:45 ` Lucas Stach
2018-03-25 10:59 ` [PATCH 5/8] drm/amdgpu: print DMA-buf status in debugfs Christian König
2018-03-25 10:59 ` Christian König
2018-03-25 10:59 ` [PATCH 6/8] drm/amdgpu: note that we can handle peer2peer DMA-buf Christian König
2018-03-25 10:59 ` Christian König
2018-03-25 10:59 ` [PATCH 7/8] drm/amdgpu: add amdgpu_gem_attach Christian König
2018-03-25 10:59 ` Christian König
2018-03-25 11:00 ` [PATCH 8/8] drm/amdgpu: add support for exporting VRAM using DMA-buf Christian König
2018-03-25 11:00 ` Christian König
2018-03-28 12:37 ` [PATCH 1/8] lib/scatterlist: add sg_set_dma_addr() helper Christoph Hellwig
2018-03-28 12:37 ` Christoph Hellwig
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