From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 85B62CA5FA1 for ; Tue, 29 Sep 2026 12:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Rya2/xvwmnG+LUNaAktFCoDG7sJ7+awgSLfG71+jbJ8=; b=06qaiatzSgHTYK2dvFgGdetsT6 krjrl7FZ/0bfeLyhxi6kqnTNlk5TIvxf45RFV30XTcBg/vROCbRI0L5iJbuIrL5xkvOhHoH7acSox rXkA9WifbQyzSzEE8sedQejzCOBthCfTvYMBSVmW+By1quhiAy4qEycc5UHP/jwDrdNbe5eHI0OrD /7Uehp43dERTUUgNcSE5AOwhw4nFu1KI8oIrE1jCD9R4um+AeXzmCHnIa4Yr7dQZJtZodeK7WGKAu TqLSlChZnT85vjRfu9ODN9BZBzxw5Bg+kWLbvJ57QURArQ6cvRty6H6kespIFnCXgV4mAA3GB7Ia6 N2fzIo4g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xBWwz-00000003Ws9-0ZrZ; Tue, 29 Sep 2026 12:28:49 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xBWwx-00000003Wrr-2Njy; Tue, 29 Sep 2026 12:28:47 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 41171412B1; Tue, 29 Sep 2026 12:28:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F8E61F000FF; Tue, 29 Sep 2026 12:28:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790684927; bh=Rya2/xvwmnG+LUNaAktFCoDG7sJ7+awgSLfG71+jbJ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=KDgs52RDTx6mh31I7eMF9UWgZiSg1uUMHsWF7NmqCu8jGXUdqsG5RRco4NAQ1yybk xQ+m+bbw1/UwtG3KjfgwVgTA5CaoLUfvpIS8lFDoTctzuu7VSyBxeowIx5ueXoinnE 8tKck5octUTdRzH9FOQQ5rKCVgLBSz3czzpqXIl3DCc+gA8SVFh5ujozuK/cQlWlr3 laRfPA3ooCYxIdbhJVJPI51VwDjiItiCpStTQWukUYuWtEtyJAROcrFDWye7LIwjKJ BEx8eFAfDOOrw/HeBkx0lBbtw4Jx8mATUrz9BoFpYrTbqm0g4vGPopfAaieDMB8Iyg sD/aDTz9tWV9g== Date: Tue, 29 Sep 2026 14:28:43 +0200 From: Maxime Ripard To: Jani Nikula Cc: Benjamin Tissoires , Neil Armstrong , Jessica Zhang , David Airlie , Simona Vetter , Maarten Lankhorst , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Florian Fainelli , Broadcom internal kernel review list , Andrzej Hajda , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Albert Esteve , Dave Stevenson , Javier Martinez Canillas , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 0/6] drm/bridge: Add a BPF-based MIPI-DSI panel driver Message-ID: References: <20260928-drm-mipi-dsi-panel-ebpf-v1-0-5244926aace4@kernel.org> <054ef52478fc93fc213a9dae23ea77f73094aaf2@intel.com> <42cfa3fb2246c66d69e45d7d9b8d6aaadc0da4c4@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="tn7gfu35hmfimxib" Content-Disposition: inline In-Reply-To: <42cfa3fb2246c66d69e45d7d9b8d6aaadc0da4c4@intel.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --tn7gfu35hmfimxib Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 0/6] drm/bridge: Add a BPF-based MIPI-DSI panel driver MIME-Version: 1.0 On Tue, Sep 29, 2026 at 01:16:41PM +0300, Jani Nikula wrote: > On Tue, 29 Sep 2026, Benjamin Tissoires wrote: > > Ouch. This immediately raises the "let's implement a parser in the > > kernel" flag, or "let's create a new langage". >=20 > Fair. >=20 > > You'd still need a dedicated driver for your new blob parser, with far > > fewer people who had had a look at it than BPF who has been working on > > for several years. >=20 > Fair. Also, it's kind of what we had with panel-mipi-dbi: https://github.com/notro/panel-mipi-dbi/wiki It didn't really take off. > > The integration of BPF and the kernel is honestly transparent nowaday: > > calling a struct_ops BPF function is just a function call away, and from > > the bpf calling anything in the kernel is also just a call away. >=20 > I don't know if I'm just being overly conservative here, but it seems to > me BPF provides too much flexibility for the use case. But maybe the > point is completely moot, and you should just ignore me. ;) >=20 > > See Maxime's answers: yes, falling back to dedicated driver is still > > encouraged. >=20 > [Moved the above to go with below.] >=20 > > Isn't that what Maxime wants to have? One driver for a plethora of DSI > > panels, with the same ability the BIOS has to also do function calls to > > set things up? >=20 > I suppose this is something that could use some clarification. Is the > idea that most (simple) dedicated panel drivers eventually get converted > to BPF? I don't think most of the existing panels will be converted, if only because it would require a different DT binding for most of them. We should totally fix the "what happens the panel is supported by a driver and the bpf driver" situation Rob (I think?) pointed out though, because I do think some will be converted still. > Or is the idea that BPF is easy for prototyping and development > using stable kernels and short time to market, and most of them would > eventually get converted to dedicated panel drivers? Even though it does make prototyping easier, I totally expect this to be a production-grade driver, just like any other panel driver. > The story wrt display before userspace is up and running also needs > clarification. Yeah, I'll work on an in-kernel loader for v2. Maxime --tn7gfu35hmfimxib Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCaruu+wAKCRAnX84Zoj2+ dvaDAYDbgFmn3VTPnwMmRkcBxrTVtKlQ2i2nTFTQqsY6+h83dQfdgZBSKyv4PaD8 t21q8pIBgLJeTlsC72CRcfaSgL7zPCcpR02uuJQEdtsW57i6k17jJYgTCB0r9j+y 8X+t6kZwEw== =GOdP -----END PGP SIGNATURE----- --tn7gfu35hmfimxib--