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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A9BBC001DC for ; Wed, 26 Jul 2023 19:54:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231910AbjGZTyO (ORCPT ); Wed, 26 Jul 2023 15:54:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230319AbjGZTyL (ORCPT ); Wed, 26 Jul 2023 15:54:11 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BCB21BF6; Wed, 26 Jul 2023 12:54:10 -0700 (PDT) Received: from nicolas-tpx395.localdomain (unknown [IPv6:2606:6d00:10:580::7a9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: nicolas) by madras.collabora.co.uk (Postfix) with ESMTPSA id 7B58D6606F8A; Wed, 26 Jul 2023 20:54:07 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1690401248; bh=UcOrA8SIWWtnawAkOkr1I4M28Jmi8tXZddLqSw+V8JU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=W16Q36YyNsYA97Y3EY732WUvNVXJ748CBu5KB/cdLIfH5F6Q1G8Bc6PeP4oxKqltI /lpeq/u1SIz5fyOGFl8fSWoEhxx8+V7Lsf3znDUt2wI+yAYhax8L/U3QjY4rmb3Xem O0i87ruJt2PcMrc1d77TEHQMxPatTKH0sxh+oDvLs/M3btjpPnBOpkOhESDZU+aNHb 2rF+glV+kl9vH8K6E1iAMLXS1Xm1FRPv90dwOOnAJxia6GoTV/LG81L9O7KWp7LSpX tICoSuuayOeGaHhbjQDFFNCjLwE+2lijQ/Rx7d52iFy+Ntmr2epmkTvR7PyBSRG4kU 1D3DdPoe7hXoQ== Message-ID: <87cfcdfadee89984496c3f52d01b4f1e10c12cae.camel@collabora.com> Subject: Re: Stateless Encoding uAPI Discussion and Proposal From: Nicolas Dufresne To: Hsia-Jun Li , Paul Kocialkowski Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Hans Verkuil , Sakari Ailus , Andrzej Pietrasiewicz , Michael Tretter , Jernej =?UTF-8?Q?=C5=A0krabec?= , Chen-Yu Tsai , Samuel Holland , Thomas Petazzoni Date: Wed, 26 Jul 2023 15:53:58 -0400 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Le mercredi 26 juillet 2023 =C3=A0 10:49 +0800, Hsia-Jun Li a =C3=A9crit=C2= =A0: > > I am strongly against this approach, instead I think we need to keep al= l > > vendor-specific parts in the kernel driver and provide a clean unified = userspace > > API. > >=20 > We are driving away vendor participation. Besides, the current design is= =20 > a performance bottleneck. I know you have been hammering this argument for many many years. But in concrete situation, we have conducted tests, and we out perform vendors sta= cks that directly hit into hardware register with stateless CODEC. Also, Paul's proposal, is that fine grain / highly close to metal tuning of the encoding process should endup in the Linux kernel, so that it can benefit from the natural hard real-time advantage of a hard IRQ. Just like anything else, we= will find a lot of common methods and shareable code which will benefit in secur= ity and quality, which is very unlike what we normally get from per vendor BSP.= The strategy is the same as everything else in Linux, vendor will adpot it if t= here is a clear benefit. And better quality, ease of use, good collection of mat= ure userspace software is what makes the difference. It does takes time of cour= se. regards, Nicolas