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Message-ID: <75d9d50fd0e6858ee05a3f2799028b8dc846ec93.camel@collabora.com>
Subject: Re: [PATCH 0/6] Initial Rust V4L2 support
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Asahi Lina <lina@asahilina.net>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Daniel Almeida <daniel.almeida@collabora.com>
Cc:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Hans Verkuil <hverkuil@xs4all.nl>, wedsonaf@gmail.com,
        ojeda@kernel.org, mchehab@kernel.org,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, kernel@collabora.com,
        Sakari Ailus <sakari.ailus@iki.fi>
Date:   Mon, 01 May 2023 16:19:35 -0400
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Le mardi 02 mai 2023 =C3=A0 05:17 +0900, Asahi Lina a =C3=A9crit=C2=A0:
> On 02/05/2023 05.10, Nicolas Dufresne wrote:
> > Le mercredi 26 avril 2023 =C3=A0 20:25 +0300, Laurent Pinchart a =C3=A9=
crit=C2=A0:
> > > Hi Daniel,
> > >=20
> > > On Wed, Apr 26, 2023 at 06:14:33PM +0100, Daniel Almeida wrote:
> > > > Hi,
> > > >=20
> > > > As I said higher up on this thread, I can maintain the Rust bits an=
d
> > > > help out with the issues around it.
> > > >=20
> > > > IMHO, we should at least try this. Who knows, it might work out :)
> > > >=20
> > > > Laurent, maybe we can take a piecemeal approach? Right now there ar=
e no
> > > > bindings for MC, but I wouldn't complain about fixing some of the C=
 code
> > > > when the time comes.
> > >=20
> > > The lifetime issues affect plain V4L2 video nodes too I'm afraid :-)
> >=20
> > Everything under the bindings is unsafe code, so it does not prevent do=
ing upper
> > implementation and have other things be memory safe. It just make Rust =
less
> > helpful in some cases (I guess everything across ops).
> >=20
> > There is low hanging fruit if some folks are interested. I see legitima=
te
> > benefit in rewriting in rust the JPEG parser, the H.264 reference list
> > generator, and maybe VP9 probability update lib. AV1 driver will need a=
 lib to
> > reduce duplicates, this could be done straight in Rust (offering a C in=
terface
> > of course, so it does not matter if the users are written in rust or C)=
.
>=20
> Unfortunately I don't think actually replacing the C implementations=20
> will be possible until Rust architecture support is on par with C, which=
=20
> probably means waiting until gccrs is ready...
>=20
> We could have both implementations until then (and only use the C one=20
> where Rust doesn't work), but the code duplication has an extra=20
> maintenance cost so it's not free. That's why people are mostly focusing=
=20
> on drivers first instead of core code.

Didn't know that, let's postpone this idea then.

thanks,
Nicolas

>=20
> ~~ Lina
>=20
>=20