From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [Ksummit-2013-discuss] [RFC] of: Allow for experimental device tree bindings Date: Thu, 24 Oct 2013 10:50:38 +0200 Message-ID: <20131024085037.GA10650@ulmo.nvidia.com> References: <1382540779-6334-1-git-send-email-treding@nvidia.com> <5267FA58.9050002@wwwdotorg.org> <20131023172001.GA3379@katana> <20131024083459.48FE3C4039D@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9amGYk9869ThD9tj" Return-path: Content-Disposition: inline In-Reply-To: <20131024083459.48FE3C4039D-WNowdnHR2B42iJbIjFUEsiwD8/FfD2ys@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: Wolfram Sang , Stephen Warren , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ksummit-2013-discuss-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org --9amGYk9869ThD9tj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 24, 2013 at 09:34:59AM +0100, Grant Likely wrote: > On Wed, 23 Oct 2013 18:20:02 +0100, Wolfram Sang wrot= e: > >=20 > > > Do we really want to polute the drivers and DT files with a ! in the > > > compatible values? I thought we'd considered that, but chosen having = the > > > drivers that use unstable bindings depend on a Kconfig option as an > > > alternative, not an additional step? > >=20 > > I'd even go further and use "unstable-" as the prefix instead of "!" > > which is way more explicit. > >=20 > >=20 > > > The one issue with doing this is that if a binding is thought to be > > > unstable, but becomes stable later without any changes, we'll have to= do > > > busy-work to remove the ! in all the DT files, thus artificially > > > introducing an incompatibility. Perhaps that's fine though? > >=20 > > I'd say yes. Going from unstable to stable is quite a step for a binding > > and that should be visible and worth a patch IMO. Also, when looking at > > a DTS file or some driver code, it will avoid > > confusion/misinterpretation if one can see immediately the status of a > > binding. >=20 > No, it shouldn't. Going from unstable to stable is not a large step, > rather it is coming to the point of looking around and realizing that > the binding is working quite well. Yes, the difference between the unstable binding before it is declared stable and the stable one shouldn't be big. In fact it should be no different at all. However the decision is still a conscious one. And it is a big step, because when you declare it stable you assert that it will never change in an incompatible way. > I don't think the solution is to put this into the kernel to be checked > at runtime. The better solution is to put it into DTC and make it > complain (either warn or error; depending on build config?) about usage > of compatible strings that are marked in the binding documentation as > unstable. Perhaps. Doing it in the kernel seemed easier. Furthermore not every user might generate their own DTB and whoever generates the DTB may not make the same choice as every user might have made. Granted, that might be a little far fetched. I personally don't mind where exactly it is checked for, as long as we can settle on something. What I'm primarily concerned about is that the current situation hinders progress and early adoption, which I consider both essential for upstream Linux development. Thierry --9amGYk9869ThD9tj Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJSaN9dAAoJEN0jrNd/PrOhxqEP/iRiQlOQOsHFBXa4ZnfnKoIu 0P/KemqXfCDkRnw8moXU/Ue+EbvZAq55M6dPtN1D1YzI4S4RE8p8c8P6jA0b8GBu 7Q9fdEJE2N+wpwt0Tpt+FS+Oos1x29xgF0tIZtKRcuC7p8o3JFMhlMWUfHnrRGow LPcVPZ76qNqEJqaBgKLlQbr6ZSYwVplzCMRu1K7Vh6PbDrLVlus4xJRNwY7tMDuL YRMnc5+ax2gi1ukGmOzH8aeKvt4tDFvp0wMBO9mLq3dGaDyccJ/nEOpCSRHid4u2 6CVx3Xl/FsLiHJh+hx8DiPlgOSvNTLaZlmiEtj2nq0to/hqtm6lM9DghS8nofmxm vceaiHYlCsIgUylUm0a2f3ZKh4tHYHzcW1Pk7crgahquJfrGpr2wTuIhlLnJi6LC CivdlA5kjTQ2LnZWxYissjPc7/4AQhXKA/m5+yyxnq7hgA04jrJsW2cic6Kon5C0 OAF3z35LyCUcZ2ZWmU42CuMsRb4Perp460lFntLgSyPLz/Q08y/UoHr3RpIT23Ec lwt1xh/S7fkzZ114ytF/LDjCS6CvMrbBtNRLa3i69654WB5hgIgwUiyl8NkuR7IE DUPK/l0tEe0qS6U63wGGXL7hGLUUMRrRVeDjpVfzcNjCZjV/Dfbc2b/SHMayHuWt ZFz0VVWMZC7fyxMya0pK =vfhU -----END PGP SIGNATURE----- --9amGYk9869ThD9tj-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html