From: Christoph Hellwig <hch@infradead.org>
To: Jonathan Marek <jonathan@marek.ca>
Cc: Christoph Hellwig <hch@infradead.org>,
freedreno@lists.freedesktop.org, Rob Clark <robdclark@gmail.com>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<linux-arm-msm@vger.kernel.org>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<dri-devel@lists.freedesktop.org>,
open list <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org, Joerg Roedel <joro@8bytes.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 2/3] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance
Date: Wed, 7 Oct 2020 07:25:19 +0100 [thread overview]
Message-ID: <20201007062519.GA23519@infradead.org> (raw)
In-Reply-To: <148a1660-f0fc-7163-2240-6b94725342b5@marek.ca>
On Tue, Oct 06, 2020 at 09:19:32AM -0400, Jonathan Marek wrote:
> One example why drm/msm can't use DMA API is multiple page table support
> (that is landing in 5.10), which is something that definitely couldn't work
> with DMA API.
>
> Another one is being able to choose the address for mappings, which AFAIK
> DMA API can't do (somewhat related to this: qcom hardware often has ranges
> of allowed addresses, which the dma_mask mechanism fails to represent, what
> I see is drivers using dma_mask as a "maximum address", and since addresses
> are allocated from the top it generally works)
That sounds like a good enough rason to use the IOMMU API. I just
wanted to make sure this really makes sense.
next prev parent reply other threads:[~2020-10-07 6:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 0:27 [PATCH 0/3] drm/msm: support for host-cached BOs Jonathan Marek
2020-10-01 0:27 ` [PATCH 1/3] drm/msm: add MSM_BO_CACHED_COHERENT Jonathan Marek
2020-10-01 23:47 ` Jordan Crouse
2020-10-01 0:27 ` [PATCH 2/3] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance Jonathan Marek
2020-10-01 23:29 ` [Freedreno] " Jordan Crouse
2020-10-02 7:53 ` Christoph Hellwig
2020-10-02 12:46 ` Jonathan Marek
2020-10-05 8:29 ` Christoph Hellwig
2020-10-05 14:35 ` Jonathan Marek
2020-10-06 7:23 ` Christoph Hellwig
2020-10-06 13:19 ` Jonathan Marek
2020-10-07 6:25 ` Christoph Hellwig [this message]
2020-10-13 13:42 ` Robin Murphy
2020-10-13 16:11 ` Rob Clark
2020-10-15 6:55 ` Christoph Hellwig
2020-10-15 15:33 ` Daniel Vetter
2020-10-15 15:43 ` Christoph Hellwig
2020-10-23 6:48 ` Christoph Hellwig
2020-10-08 8:27 ` Joerg Roedel
2020-10-01 0:27 ` [PATCH 3/3] drm/msm: bump up the uapi version Jonathan Marek
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