From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Reichel Subject: Re: [PATCH v4 2/8] OF: Introduce DT overlay support. Date: Mon, 26 May 2014 17:09:44 +0200 Message-ID: <20140526150942.GA26787@earth.universe> References: <20140516105814.3EA3FC403C2@trevor.secretlab.ca> <20140520055026.E3A98C412DA@trevor.secretlab.ca> <20140526104824.63F13C42129@trevor.secretlab.ca> <20140526112348.907B7C421A5@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Dxnq1zWXvFF0Q93v" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Pantelis Antoniou Cc: Grant Likely , Geert Uytterhoeven , Rob Herring , Stephen Warren , Matt Porter , Koen Kooi , Alison Chaiken , Dinh Nguyen , Jan Lubbe , Alexander Sverdlin , Michael Stickel , Guenter Roeck , Dirk Behme , Alan Tull , Sascha Hauer , Michael Bohan , Ionut Nicu , Michal Simek , Matt Ranostay , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Pete Popov List-Id: devicetree@vger.kernel.org --Dxnq1zWXvFF0Q93v Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Mon, May 26, 2014 at 02:55:37PM +0300, Pantelis Antoniou wrote: > On May 26, 2014, at 2:23 PM, Grant Likely wrote: > > On Mon, 26 May 2014 12:57:32 +0200, Geert Uytterhoeven wrote: > > Heeheehee. We're back where we started. The original question is whether > > or not that is a valid approach. If the overlay represents something > > that can be hot plugged/unplugged, then passing it through to the second > > kernel would be the wrong thing to do. If it was a permenant addition, > > then it probably doesn't need to be removed. > >=20 > > We do actually keep the overlay info in memory for the purpose of > > removal exactly so we can support hot unbinding of devices and drivers > > that make use of overlays. >=20 > We can support either method. I am not feeling any wiser about which one = should be > the default TBH, so what about exporting a property and let the platform= =20 > figure out which is more appropriate? What about supporting "negative" overlays (so an overlay, that removes DT entries)? That way one could reverse apply an overlay. All the dependency stuff would basically be the users problem. The kernel only checks if it can apply an overlay (and return some error code if it can't). This this code is needed anyway to check the input from userspace. As a result the overlay handling would basically have the same behaviour as diff and patch :) P.S.: Sorry if this has already been suggested. I have only read mails from PATCHv4. -- Sebastian --Dxnq1zWXvFF0Q93v Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJTg1k2AAoJENju1/PIO/qauC4P/R59MM9Uon5O924VUUsCLfKQ zcICgBs8a6NvaJmo83pQYPIPgwGY9dmkT6i8OSCPPIY6RELsOTh2e0ClEjAGZyzX Hw+16jMd7it7dH7EFufC2eOHAZRyqRkOk/oo6JIomboBBg3tBiQHe7JjOddZuZKR JAv23xp1RcQwnBsAC8qkum3ELcaHciRhWS1r4kmrDATPAhTWqvUMPlieHGXA89Qx HJYxMTXxxdMvdFopmitnVKa7NUI3m/lyF2frWrkgDWx7lZ3iWqii8iJrxlAi2E2k BgiFTEq//ZCEHy51PkFtpyNGag7llkzJSupDbudUV/ZZoURVV955qIZluCCusj34 NlRKacA047DpFohakWsHfQXo4xCIRQPy22byrNEqM/pZs7sFq3b8ZwaUfV8FIJU1 8QMbujEZ/4MCAAJBkpR9xiAeZXJ5chgcUZJfd9fiM1lQn10M0KOX+KhnpquyWsbs o4IT/9YfblBRnfaToBhflf8YsO+K5bgz1B4gyti/TjFQNm4tjG1jmZdFjuDnd+jv CnBpUQYxiX1Qtqh8AsjYdqaCEjEWM2mF3cOfnufKuaL+7SqLjS9gPow/0OPx8P9n gWJe8YxhkVajXscUMu/Cdn+l2l6XsMc9m7IUM0ZnwYB0RMPE+aD/yLu1QnXRz14e YWfgcyJOopecI4o+f5C7 =KgqV -----END PGP SIGNATURE----- --Dxnq1zWXvFF0Q93v--