From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Simon Ser <contact@emersion.fr>
Cc: "Maxime Ripard" <mripard@redhat.com>,
"Bryan O'Donoghue" <bryan.odonoghue@linaro.org>,
"Dmitry Baryshkov" <dmitry.baryshkov@linaro.org>,
"Hans de Goede" <hdegoede@redhat.com>,
"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>,
"Andrey Konovalov" <andrey.konovalov.ynk@gmail.com>
Subject: Re: Safety of opening up /dev/dma_heap/* to physically present users (udev uaccess tag) ?
Date: Wed, 22 May 2024 09:02:21 -0400 [thread overview]
Message-ID: <656423737618913a19633b4b4c39e2e8de54546d.camel@collabora.com> (raw)
In-Reply-To: <20240516112055.GB5253@pendragon.ideasonboard.com>
Le jeudi 16 mai 2024 à 14:20 +0300, Laurent Pinchart a écrit :
> On Thu, May 16, 2024 at 07:00:31AM +0000, Simon Ser wrote:
> > On Tuesday, May 14th, 2024 at 22:42, Laurent Pinchart wrote:
> >
> > > My experience on Arm platforms is that the KMS drivers offer allocation
> > > for scanout buffers, not render buffers, and mostly using the dumb
> > > allocator API. If the KMS device can scan out YUV natively, YUV buffer
> > > allocation should be supported. Am I missing something here ?
> >
> > Note that dumb buffers are only intended for simple software-rendering
> > use-cases. Anything more complicated (e.g. involving GPU rendering)
> > should use another mechanism.
>
> Sure. Even if dumb buffers may work for GPU rendering in some cases,
> there's no guarantee they will, so they shouldn't be used.
>
> My comment was related to scanout buffers, as I was puzzled by Nicolas
> mentioning how "KMS drivers only offer allocation for render buffers".
> On Arm platforms the render buffers are allocated on the GPU's DRM
> device as far as I understand, while the KMS drivers allocate scanout
> buffers using the dumb buffers API.
>
The message is getting distorted. I'm saying that not all supported formats have
an allocation API in DRM/KMS drivers. Most YUV formats needed for media handling
(GPU or scannout) are not supported.
Nicolas
p.s. I feel like commenters thinks its evident for userspace application to know
if they are doing scanout or GPU ... while in reality, they offload their
allocated buffer to a compositor which will have to dynamically juggle between
these two with its own heuristic.
next prev parent reply other threads:[~2024-05-22 13:02 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
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 [this message]
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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