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 182213FC3 for ; Sat, 11 Sep 2021 11:42:16 +0000 (UTC) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id BAE7FDD; Sat, 11 Sep 2021 13:42:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1631360534; bh=+x33wMsmySy23XlwhuagP3CbYN1bE2ILek9jqpbOpXc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=V/O+CT8GjMVvvYdmUCYxeBCSbFvlBt8Jcvip1iD4y6xJGLt0+gkPreXDMNDJyq/oM F1J+zJwCquQKpfwypbEqXFmzrT6FeNpWWuj3HhprrKbxTOlkPM1Zub49PG6F3f1s6y 0yyJ2y0gIABJC5/Qgb7gc58Z1/uWnZ5MxRMMYoyo= Date: Sat, 11 Sep 2021 14:41:52 +0300 From: Laurent Pinchart To: Leon Romanovsky Cc: Thomas Gleixner , Josh Triplett , Mauro Carvalho Chehab , Jonathan Corbet , ksummit@lists.linux.dev Subject: Re: [MAINTAINER SUMMIT] User-space requirements for accelerator drivers Message-ID: References: <877dfop2lx.fsf@meer.lwn.net> <20210911005214.71b55ac6@coco.lan> <87ilz8c7ff.ffs@tglx> 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 In-Reply-To: On Sat, Sep 11, 2021 at 01:31:02PM +0300, Leon Romanovsky wrote: > On Sat, Sep 11, 2021 at 01:55:16AM +0200, Thomas Gleixner wrote: > > On Fri, Sep 10 2021 at 16:45, Josh Triplett wrote: > > > > > On Sat, Sep 11, 2021 at 12:52:14AM +0200, Mauro Carvalho Chehab wrote: > > >> On media, enforcing userspace to always be open source would > > >> have been very bad, as it would prevent several videoconferencing > > >> software to exist on Linux. > > > > > > I don't think we should enforce that all userspace users of an interface > > > be Open Source. I do think we should enforce that *some* userspace user > > > of an interface be Open Source before we add the interface. > > > > The real question is whether the interface is documented in a way that > > an Open Source implementation is possible. It does not matter whether it > > exists at that point in time or not. Even if it exists there is no > > guarantee that it is feature complete. > > > > Freely accessible documentation is really the key. > > I have more radical view than you and think that documentation is far > from being enough. I would like to see any userspace API used (or to be > used) in any package which exists in Debiam/Fedora/SuSE. We probably need to add Android AOSP to that list, as we have Android-specific APIs (not that I believe we *should* have Android-specific APIs, there's been lots of efforts over the past years to develop standard APIs for use cases that stem from Android, slowly replacing Android-specific APIs in some area, but I don't believe we can realisticly bridge that gap completely overnight, if ever). > Only this will give us some sort of confidence that API and device are usable > to some level. As a side note, we will be able to estimate possible API > deprecation/fix/extension based on simple search in package databases. Linux supports devices from very diverse markets, from very tiny embedded devices to supercomputers. We have drivers for devices that exist in data centres of a single company only, or for which only a handful of units exist through the world. The set of rules that we'll decide on, if any, should take this into account. > IMHO, github projects to show API usage are the worst possible way to > allow acceptance for new userspace API. -- Regards, Laurent Pinchart