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Subject: Re: [PATCH v7 2/9] media: vivid: Convert to v4l2_ext_pix_format
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Tomasz Figa <tfiga@chromium.org>
Cc:     Randy Li <ayaka@soulik.info>, linux-media@vger.kernel.org,
        randy.li@synaptics.com, Brian.Starkey@arm.com,
        boris.brezillon@collabora.com, frkoenig@chromium.org,
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        narmstrong@baylibre.com, sakari.ailus@iki.fi,
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        Helen Koike <helen.koike@collabora.com>
Date:   Fri, 04 Aug 2023 16:19:18 -0400
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Le vendredi 28 juillet 2023 =C3=A0 16:22 +0900, Tomasz Figa a =C3=A9crit=C2=
=A0:
> > For MPLANE, where backward compatibility was built into libv4l2 LD_PREL=
OAD
> > wrapper,
>=20
> Could you refresh my memory on what kind of backwards compatibility we
> had in libv4l2? Was that to make it possible to use new MPLANE-only
> drivers with old applications?

https://git.linuxtv.org/v4l-utils.git/tree/lib/libv4l-mplane

It does some "magic" trick due to some of the new fields not guarantied to =
be
zero, translate the type, the capabilities. Strangely it does not filter th=
e
pixel formats. I suspect it assumes legacy application won't know about the=
 new
one and will just ignore/not use them.

Nicolas