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From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Hans de Goede <hdegoede@redhat.com>
Cc: "Sumit Semwal" <sumit.semwal@linaro.org>,
	"Benjamin Gaignard" <benjamin.gaignard@collabora.com>,
	"Brian Starkey" <Brian.Starkey@arm.com>,
	"John Stultz" <jstultz@google.com>,
	"T.J. Mercier" <tjmercier@google.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Lennart Poettering" <mzxreary@0pointer.de>,
	"Robert Mader" <robert.mader@collabora.com>,
	"Sebastien Bacher" <sebastien.bacher@canonical.com>,
	"Linux Media Mailing List" <linux-media@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	linaro-mm-sig@lists.linaro.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Milan Zamazal" <mzamazal@redhat.com>,
	"Maxime Ripard" <mripard@redhat.com>,
	"Andrey Konovalov" <andrey.konovalov.ynk@gmail.com>
Subject: Re: Safety of opening up /dev/dma_heap/* to physically present users (udev uaccess tag) ?
Date: Tue, 7 May 2024 16:15:05 +0100	[thread overview]
Message-ID: <d2a512b2-e6b1-4675-b406-478074bbbe95@linaro.org> (raw)
In-Reply-To: <e7ilwp3vc32xze3iu2ejgqlgz44codsktnvyiufjhuf2zxcnnf@tnwzgzoxvbg2>

On 07/05/2024 16:09, Dmitry Baryshkov wrote:
> Ah, I see. Then why do you require the DMA-ble buffer at all? If you are
> providing data to VPU or DRM, then you should be able to get the buffer
> from the data-consuming device.

Because we don't necessarily know what the consuming device is, if any.

Could be VPU, could be Zoom/Hangouts via pipewire, could for argument 
sake be GPU or DSP.

Also if we introduce a dependency on another device to allocate the 
output buffers - say always taking the output buffer from the GPU, then 
we've added another dependency which is more difficult to guarantee 
across different arches.

---
bod

  reply	other threads:[~2024-05-07 15:15 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-06 11:49 Safety of opening up /dev/dma_heap/* to physically present users (udev uaccess tag) ? Hans de Goede
2024-05-06 12:05 ` Maxime Ripard
2024-05-06 12:11   ` Hans de Goede
2024-05-06 13:38   ` Daniel Vetter
2024-05-06 14:01     ` Hans de Goede
2024-05-07 11:15       ` Daniel Vetter
2024-05-08  5:46         ` Daniel Stone
2024-05-08  8:33           ` Daniel Vetter
2024-05-08  8:38             ` Daniel Stone
2024-05-08 15:49               ` Daniel Vetter
2024-05-09  9:23                 ` Daniel Stone
2024-05-16 10:18                   ` Daniel Vetter
2024-05-13 13:51                 ` Simon Ser
2024-05-16 10:13                   ` Daniel Vetter
2024-05-07 13:34       ` Dmitry Baryshkov
2024-05-07 18:59     ` Laurent Pinchart
2024-05-22 13:34     ` Maxime Ripard
2024-05-23  9:41       ` Daniel Vetter
2024-05-07 13:32 ` Dmitry Baryshkov
2024-05-07 14:34   ` Hans de Goede
2024-05-07 15:09     ` Dmitry Baryshkov
2024-05-07 15:15       ` Bryan O'Donoghue [this message]
2024-05-07 15:19         ` Dmitry Baryshkov
2024-05-07 18:40           ` Laurent Pinchart
2024-05-07 19:59             ` Dmitry Baryshkov
2024-05-07 20:15               ` Laurent Pinchart
2024-05-08  8:39               ` Daniel Vetter
2024-05-08 21:54                 ` Laurent Pinchart
2024-05-13  8:39               ` Maxime Ripard
2024-05-07 17:36         ` Daniel Vetter
2024-05-07 18:36           ` Laurent Pinchart
2024-05-07 20:07             ` Nicolas Dufresne
2024-05-08  8:36               ` Daniel Vetter
2024-05-08 21:51                 ` Laurent Pinchart
2024-05-08 21:52                   ` Laurent Pinchart
2024-05-13  8:29                 ` Maxime Ripard
2024-05-13  8:34                   ` Laurent Pinchart
2024-05-13 15:10                     ` Nicolas Dufresne
2024-05-14 20:42                       ` Laurent Pinchart
2024-05-15 17:43                         ` nicolas.dufresne
2024-05-16 11:27                           ` Laurent Pinchart
2024-05-16 17:11                             ` nicolas.dufresne
2024-05-21  8:43                               ` Maxime Ripard
2024-05-21 14:18                                 ` nicolas.dufresne
2024-05-16  7:00                         ` Simon Ser
2024-05-16 11:20                           ` Laurent Pinchart
2024-05-22 13:02                             ` Nicolas Dufresne
2024-05-13 13:42                   ` Nicolas Dufresne
2024-05-13 13:51                     ` Maxime Ripard
2024-05-13 15:06                       ` Nicolas Dufresne
2024-05-14 20:45                         ` Laurent Pinchart
2024-05-14 20:52                           ` Nicolas Dufresne

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