From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from leonov.paulk.fr (leonov.paulk.fr [185.233.101.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CE27430BAA for ; Mon, 2 Mar 2026 18:50:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.233.101.22 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772477428; cv=none; b=d9jD3qfz2D0iPawe7DQf1L+cLRl/pZYbACMHEqysAfx9IMPC5lXlU2J3pAkeypdS5stvmBfYPhRYSIn1PjQ8TULssXaJVIQQT69nGj5WIKbT0iYxSlm5ur+lyYRZYigA4NdAwkb7GrQlZTQxX8AqhD9wsrVKbpUZPWmqZTtyKgE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772477428; c=relaxed/simple; bh=AUZd2qeBB4ymh338SP2zH0V8AeyE+PzYBbT3I+g2Y2I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NnlH+VnhQvOgKApOmi+b4PD0Od8ppW6aknXEvI5FpQBqRnhw5D0sv9LpFe3nmRxPCCF+lVKX+MWhOnQwtxbYLZIC7C9MJtIyhcB+LwkprKXpkhU+pQJJCUD8xSNYnee0GbsTMwyRjLfOnMh++dgcl0z2pTmBLf7gKxQizXtCNJ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sys-base.io; spf=pass smtp.mailfrom=sys-base.io; arc=none smtp.client-ip=185.233.101.22 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sys-base.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sys-base.io Received: from laika.paulk.fr (12.234.24.109.rev.sfr.net [109.24.234.12]) by leonov.paulk.fr (Postfix) with ESMTPS id B67D81F8004A for ; Mon, 2 Mar 2026 18:41:31 +0000 (UTC) Received: by laika.paulk.fr (Postfix, from userid 65534) id 497FAB24E3A; Mon, 2 Mar 2026 18:41:29 +0000 (UTC) X-Spam-Level: Received: from shepard (unknown [192.168.1.1]) by laika.paulk.fr (Postfix) with ESMTPSA id 93D00B24E34; Mon, 2 Mar 2026 18:41:26 +0000 (UTC) Date: Mon, 2 Mar 2026 19:41:24 +0100 From: Paul Kocialkowski To: Laurent Pinchart Cc: Nicolas Dufresne , Hans Verkuil , Linux Media Mailing List , Mauro Carvalho Chehab , Sean Young , Sakari Ailus , Ricardo Ribalda , Jacopo Mondi , Niklas =?utf-8?Q?S=C3=B6derlund?= , Tomi Valkeinen , Alain Volmat , Bryan O'Donoghue , Dave Stevenson , Daniel Almeida , Michael Tretter , Tomasz Figa , Steve Cho , Kieran Bingham , Kevin Hilman , Benjamin Mugnier , Hans de Goede , Maxime Ripard Subject: Re: [ANN] Media Summit on May 26th in Nice, France Message-ID: References: <92e24f36-d189-4ba8-ad0b-43277bc1aabd@kernel.org> <2f0c3f41-93fa-4a1f-aad2-b59ebbc59909@kernel.org> <20260301150259.GD2860169@killaraus.ideasonboard.com> <77aff6321715c2141257d1f114c6bd70c7ac2d29.camel@collabora.com> <20260302140154.GA3360678@killaraus.ideasonboard.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="TaKVmHRiGDv6tWVK" Content-Disposition: inline In-Reply-To: <20260302140154.GA3360678@killaraus.ideasonboard.com> --TaKVmHRiGDv6tWVK Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Mon 02 Mar 26, 15:01, Laurent Pinchart wrote: > On Mon, Mar 02, 2026 at 08:55:05AM -0500, Nicolas Dufresne wrote: > > Le dimanche 01 mars 2026 =C3=A0 16:02 +0100, Laurent Pinchart a =C3=A9c= rit=C2=A0: > > > I would also like to revive efforts to properly support dmabuf import > > > for multi-planar formats with configurable plane offsets (a.k.a. data > > > offsets), but I think this requires a champion to resume the work more > > > than a discussion at the media summit. > >=20 > > I haven't sent my RFC yet about that subject, that will probably be aft= er > > Embedded World. But I think it can serve as example of "possible" way f= orward. > > And I believe the ChromeOS request should be cited. I think we need mor= e then a > > champion to resume the work, since I personally don't believe in the an= cient > > proposal from Collabora. I'd say plan for a little more time on this su= bject. >=20 > Maybe it could then make sense to brainstorm the topic during the media > summit. I'm also interested in the topic and had a first go at it a few months back, with code at: https://git.paulk.fr/projects/linux.git/log/?h=3Dmedia/dmabuf= -offset This is based on our discussions on IRC, with the main concern that hardware units may have specific alignment constraints that apply, so not all offsets are valid and drivers need to provide their alignment constraints. So the feature is disabled by default and drivers that want to support it need to provide their alignment constraint. It is then reported to userspace via create_buffers and a new flag is added to indicate that the driver supports the feature. Then it comes down to adding the offset down to videobuf2, which is straightforward in some cases (that I implemented) and less so in others, l= ike sg tables (which I didn't implement). So it feels like more work would be needed to get the vb2 side right. Nicolas, did you have another approach in mind or is your RFC based on the = same ideas? > > If possible, I would like to add to the agenda a short update related t= o Vulkan > > Video side of CODECs, what are the viable options for Linux Media and w= hat is in > > preparation outside of our subsystem. The second aspect is informative = as these > > discussion don't seem to lean toward our subsystem as the foundation. B= ut I > > think its rather useful for everyone to understand why and what is incl= uded. >=20 > I'd be interested in hearing about that. Yes me too. I guess this more or less boils down to the long-time debate of generic uAPI with complexity in the kernel vs driver-specific uAPI with complexity in userspace. I still think a generic uAPI for codecs makes good sense, but I understand the appeal of something more similar to drm accel. All the best, Paul --=20 Paul Kocialkowski, Independent contractor - sys-base - https://www.sys-base.io/ Free software developer - https://www.paulk.fr/ Expert in multimedia, graphics and embedded hardware support with Linux. --TaKVmHRiGDv6tWVK Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEAbcMXZQMtj1fphLChP3B6o/ulQwFAmml2dQACgkQhP3B6o/u lQytMQ//dXN29UvsKv8aI4loVMsgNA+/LoZ0LZjlK1uoISwnuW1H0hxVXLWIMj+j te6m76I75UiI5xPuEOl/e84eolyAF/jhcciWaMCFRze8efpvy4JikHxdS/rPKdqB zWFpNb8vgzhjFwbmTWjtfM9HeP6SZpBzdf/CoM2oVhxz1RATTl1GT921NZh1yxN7 oT8l8k4HgCid8OUpxBKo6uvbs74v/bF84hdVo13erPLx4Xjf/JHARIKvYJKvK7Kg 4DdVorp7+XR9FSGX+imuvkVeq7ivZtAeUEra5gIN8CVlnCyYivQsPP/blrAOixOu DIlG52Tmu/X8G+PC810jVPOFgeZ17sgQINofoVV/lBGLCKijO0ATWVxtk5/nswZf 7FhErTSYe7iU0lX3/cIXa8y5YD4IuSb8x03byu2nx5fn/UPivEjAxOtAaebv+aFV wBUnSoNhQtv+hfM4IwEPJ7s2X/89Q/nxZ2zKfgdAiEMbVmwlgDGW+umXiBcRv2Cl XGs9Se61X3IKyJOKnb3+sGkcukmPIEvi87DymbZtrMy8RFFCgIlHhprUysjx4Lnp Rbf2O/59zqW/szJ2entVuzUhB9eHP+vnkVvAq1tJZ3NJ3zUCI/8xkL71Kn3uM2jR QiR9SlJhEd8CYf29lKyiYmHp8dlcyibLvFIYe/bbOSfc1MUdQ7w= =c494 -----END PGP SIGNATURE----- --TaKVmHRiGDv6tWVK--