From: Christoph Hellwig <hch@lst.de>
To: Brian Starkey <Brian.Starkey@arm.com>
Cc: Christoph Hellwig <hch@lst.de>,
"Clark, Rob" <robdclark@gmail.com>,
Dave Airlie <airlied@linux.ie>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Tomasz Figa <tfiga@chromium.org>,
Sean Paul <seanpaul@chromium.org>,
"vivek.gautam@codeaurora.org" <vivek.gautam@codeaurora.org>,
freedreno <freedreno@lists.freedesktop.org>,
Robin Murphy <Robin.Murphy@arm.com>, nd <nd@arm.com>
Subject: Re: [PATCH v3 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg*
Date: Thu, 29 Nov 2018 19:35:50 +0100 [thread overview]
Message-ID: <20181129183550.GD30281@lst.de> (raw)
In-Reply-To: <20181129173301.rye77slpy27regi5@DESKTOP-E1NTVVP.localdomain>
On Thu, Nov 29, 2018 at 05:33:03PM +0000, Brian Starkey wrote:
> This sounds very useful for ion, to avoid CPU cache maintenance as
> long as the buffer stays in device-land.
>
> One question though: How would you determine "the last user to unmap"
> to know when to do the final "make visible to CPU" step?
I'd assume the user of the DMA API keeps track of it. E.g. dmabuf
would be a pretty natural layer to implement common logic for this.
next prev parent reply other threads:[~2018-11-29 18:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 14:03 [PATCH v3 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg* Vivek Gautam
2018-11-29 14:14 ` Christoph Hellwig
2018-11-29 14:25 ` Rob Clark
2018-11-29 14:42 ` Rob Clark
2018-11-29 15:54 ` Christoph Hellwig
2018-11-29 18:48 ` Rob Clark
2018-11-29 19:40 ` Jordan Crouse
2018-11-29 19:57 ` Tomasz Figa
2018-11-29 20:03 ` Robin Murphy
2018-11-30 0:23 ` Tomasz Figa
2018-12-01 2:05 ` Tomasz Figa
2018-12-01 11:46 ` Rob Clark
2018-12-03 0:12 ` Tomasz Figa
2018-11-29 14:43 ` Daniel Vetter
2018-11-29 15:57 ` Christoph Hellwig
2018-11-29 16:28 ` Daniel Vetter
2018-11-29 16:57 ` Christoph Hellwig
2018-11-29 17:09 ` Daniel Vetter
2018-11-29 17:24 ` Tomasz Figa
2018-11-29 18:35 ` Christoph Hellwig
2018-11-29 18:57 ` Rob Clark
2018-11-30 9:40 ` Daniel Vetter
2018-11-30 9:35 ` Daniel Vetter
2018-11-30 9:44 ` Christoph Hellwig
2018-11-29 18:33 ` Christoph Hellwig
2018-11-30 9:46 ` Daniel Vetter
2018-12-07 1:38 ` Christoph Hellwig
2018-12-07 14:29 ` Rob Clark
2018-11-29 17:33 ` Brian Starkey
2018-11-29 18:35 ` Christoph Hellwig [this message]
2018-11-30 1:15 ` Rob Clark
2018-11-30 9:35 ` Christoph Hellwig
2018-11-29 15:53 ` Christoph Hellwig
2018-11-29 18:44 ` Rob Clark
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