From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 28DE134545 for ; Sun, 28 Jul 2024 11:24:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722165861; cv=none; b=k7RCXtrmhW2z1ejP+9HADHlrZQ/MuBlmujwUBiiBd75zvMax1zikt0mzLG7g+5y9dlJCB0knruZo+XK7HNAPMo9JpVQRXQV6HBPh8tWD/3fsGz90xzicPxlnvA7ozbZQjSUbF7SWPw8TX+YWJf5UxBWzoc6zfm7dzHyG/A/bT1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722165861; c=relaxed/simple; bh=fTmj/tmttMD10/Ye6QDuNXMP2HnhPPV1mrdv0xVXghI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LZaoDOUNiHbOniO1NLjROMu0SAKy2UMsPTI5wPTjHhqtxns3FhuGv92fm7SG3xGXTZk22HEdLaK98C6WF45FEfAl9uHxt1sD5x2w8zEePvDn7oa7JH//FhKk/WuFh3kzaPDDtv7rlfyJIGb+AC9TciH3fqlyc4zD7SLSBE+KHng= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=XX8p+fvZ; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="XX8p+fvZ" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 9DC4363F; Sun, 28 Jul 2024 13:23:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1722165812; bh=fTmj/tmttMD10/Ye6QDuNXMP2HnhPPV1mrdv0xVXghI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XX8p+fvZPGAOUl7ZWiMIZuuqizXm9HepnVs5aOxKO62BD+v8FL4+UXIkPMtKdofzt 5BWdPd6A4By9drzGMlIZJQwkgmKz1IhzRjGi66XNTsQO59Lns4O+UyH7BMqNf2HKwh mndiHF0FaragnHwFv+5dxTwB3LQlPCDXSeGrSiZU= Date: Sun, 28 Jul 2024 14:23:58 +0300 From: Laurent Pinchart To: Ricardo Ribalda Delgado Cc: Leon Romanovsky , James Bottomley , Jiri Kosina , Dan Williams , ksummit@lists.linux.dev, linux-cxl@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, jgg@nvidia.com Subject: Re: [MAINTAINERS SUMMIT] Device Passthrough Considered Harmful? Message-ID: <20240728112358.GB30973@pendragon.ideasonboard.com> References: <1e82a5c97e915144e01dd65575929c15bc0db397.camel@HansenPartnership.com> <20240724200012.GA23293@pendragon.ideasonboard.com> <20240725122315.GE7022@unreal> <20240725132035.GF7022@unreal> <20240725194202.GE14252@pendragon.ideasonboard.com> <20240726131110.GD28621@pendragon.ideasonboard.com> Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Jul 26, 2024 at 05:40:50PM +0200, Ricardo Ribalda Delgado wrote: > On Fri, Jul 26, 2024 at 3:11 PM Laurent Pinchart > wrote: > > > > On Fri, Jul 26, 2024 at 10:02:27AM +0200, Ricardo Ribalda Delgado wrote: > > > On Thu, Jul 25, 2024 at 9:44 PM Laurent Pinchart wrote: > > > > On Thu, Jul 25, 2024 at 04:20:35PM +0300, Leon Romanovsky wrote: > > > > > On Thu, Jul 25, 2024 at 03:02:13PM +0200, Ricardo Ribalda Delgado wrote: > > > > > > On Thu, Jul 25, 2024 at 2:23 PM Leon Romanovsky wrote: > > > > > > > On Thu, Jul 25, 2024 at 11:26:38AM +0200, Ricardo Ribalda Delgado wrote: > > > > > > > > On Wed, Jul 24, 2024 at 10:02 PM Laurent Pinchart wrote: > > > > > > > > > > > > > > <...> > > > > > > > > > > > > > > > It would be great to define what are the free software communities > > > > > > > > here. Distros and final users are also "free software communities" and > > > > > > > > they do not care about niche use cases covered by proprietary > > > > > > > > software. > > > > > > > > > > > > > > Are you certain about that? > > > > > > > > > > > > As a user, and as an open source Distro developer I have a small hint. > > > > > > But you could also ask users what they think about not being able to > > > > > > use their notebook's cameras. The last time that I could not use some > > > > > > basic hardware from a notebook with Linux was 20 years ago. > > > > > > > > > > Lucky you, I still have consumer hardware (speaker) that doesn't work > > > > > with Linux, and even now, there is basic hardware in my current > > > > > laptop (HP docking station) that doesn't work reliably in Linux. > > > > > > > > > > > > > They only care (and should care) about normal workflows. > > > > > > > > > > > > > > What is a normal workflow? > > > > > > > Does it mean that if user bought something very expensive he > > > > > > > should not be able to use it with free software, because his > > > > > > > usage is different from yours? > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > It means that we should not block the standard usage for 99% of the > > > > > > population just because 1% of the users cannot do something fancy with > > > > > > their device. > > > > > > > > > > Right, the problem is that in some areas the statistics slightly different. > > > > > 99% population is blocked because 1% of the users don't need it and > > > > > don't think that it is "normal" flow. > > > > > > > > > > > Let me give you an example. When I buy a camera I want to be able to > > > > > > do Video Conferencing and take some static photos of documents. I do > > > > > > not care about: automatic makeup, AI generated background, unicorn > > > > > > filters, eyes recentering... But we need to give a way to vendors to > > > > > > implement those things closely, without the marketing differentiators, > > > > > > vendors have zero incentive to invest in Linux, and that affects all > > > > > > the population. > > > > > > > > I've seen these kind of examples being repeatedly given in discussions > > > > related to camera ISP support in Linux. They are very misleading. These > > > > are not the kind of features that are relevant for the device > > > > pass-through discussion these day. Those are high-level use cases > > > > implemented in userspace, and vendors can ship any closed-source > > > > binaries they want there. What I care about is the features exposed by > > > > the kernel to userspace API. > > > > > > The ISPs are gradually becoming programmable devices and they indeed > > > help during all of those examples. > > > > I'd like to see more technical information to substantiate this claim. > > So far what I've sometimes seen is ISPs that include programmable > > elements, but hiding those behind a firmware that exposes a fixed > > (configurable) pipeline. I've also heard of attempts to expose some of > > that programmability to the operating system, which were abandoned in > > the end due to lack usefulness. > > > > > Userspace needs to send/receive information from the ISP, and that is > > > exactly what vendors want to keep in the close. > > > > But that's exactly what we need to implement an open userspace ecosystem > > :-) > > > > > Describing how they implement those algorithms is a patent minefield > > > and their differentiating factor. > > > > Those are also arguments I've heard many times before. The > > differentiating factor for cameras today is mostly in userspace ISP > > control algorithms, and nobody is telling vendors they need to open all > > that. > > I disagree. The differentiating factor is what the ISP is capable of > doing and how they do it. Otherwise we would not see new ISPs in the > market. Hardware certainly evolves, but it's far from being the main differentiating factor in the markets and use cases you're usually referring to. > If you define the arguments passed to an ISP you are defining the > algorithm, and that is a trade secret and/or a patent violation. Are you confusing ISP processing blocks, sometimes referred to as algorithms, and ISP control algorithms ? There is absolutely no way to do anything with an ISP, not even the bare minimum, if you don't know what parameters to pass to it. > > When it comes to patents, we all know how software patents is a > > minefield, and hardware is also affected. I can't have much sympathy for > > this argument though, those patents mostly benefit the largest players > > in the market, and those are the ones who currently claim they can't > > open anything due to patents. > > Big players do not usually sue each other. The big problem is patent > trolls that "shoot at everything that moves". > > I dislike patents, but it is the world we have to live in. No vendor > is going to take our approach if they risk a multi million dollar > lawsuit. When was the last time anyone heard of big players pushing to reform the patent system ? At best there are initiatives such as OIN, which some large companies have supporting. It's still a workaround though. > > > > > > This challenge seems to be solved for GPUs. I am using my AMD GPU > > > > > > freely and my nephew can install the amdgpu-pro proprietary user space > > > > > > driver to play duke nukem (or whatever kids play now) at 2000 fps. > > > > > > > > > > > > There are other other subsystems that allow vendor passthrough and > > > > > > their ecosystem has not collapsed. > > > > > > > > > > Yes, I completely agree with you on that. > > > > > > > > > > > Can we have some general guidance of what is acceptable? Can we define > > > > > > together the "normal workflow" and focus on a *full* open source > > > > > > implementation of that? > > > > > > > > > > I don't think that is possible to define "normal workflow". Requirement > > > > > to have open-source counterpart to everything exposed through UAPI is a > > > > > valid one. I'm all for that. > > > > > > > > That's my current opinion as well, as least when it comes to the kernel > > > > areas I mostly work with. -- Regards, Laurent Pinchart