From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1cDoed-0001Ql-CY for barebox@lists.infradead.org; Mon, 05 Dec 2016 08:29:44 +0000 Date: Mon, 5 Dec 2016 09:29:19 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Message-ID: <20161205082919.vbqtltxd43jw4qvj@pengutronix.de> References: <1480618503-11376-1-git-send-email-akurz@blala.de> <1480671998.17003.37.camel@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1480671998.17003.37.camel@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] bootm: dont use internal oftree fallback by default To: Lucas Stach Cc: barebox@lists.infradead.org, Alexander Kurz On Fri, Dec 02, 2016 at 10:46:38AM +0100, Lucas Stach wrote: > Am Donnerstag, den 01.12.2016, 19:55 +0100 schrieb Alexander Kurz: > > Booting via bootm offers several methods to load oftree data. When no > > dedicated oftree image is provided, barebox checks for the presence of > > its own internal oftree, assuming it as a good choice for boot. > > = > > This fallback method breaks the usecase when a modern OF-based barebox > > is used to boot a legacy ATAG dependent non OF based vendor provided ke= rnel > > (e.g. ATAGs will be switched off). > > Unfortunately those kernels are being still actively shipped today. > > = > > Change barebox according to the principle of least surprise: when no > > oftree data is proactively configured, then perform a non-oftree boot. > > Make the fallback-use of the barebox internal oftree an opt-in feature. > > = > > Note: this will break boards where the boot process relied on this feat= ure, > > e.g.: oftree based barebox plus oftree based kernel without an explicit > > given dts. For those boards global.bootm.internal_oftree_fallback=3D1 s= hould > > be set. > > = > The least surprise on a modern oftree based kernel is that the firmware > (Barebox) provides the DT, if there isn't an explicit override. > = > So NACK on the patch in it's current form. If you have a board where you > know that the kernel doesn't play along, you may reverse this patch so > that you can set global.bootm.no_internal_oftree=3D1 in your board code. Ack for the NAck. And AFAIK you can already today just do oftree -f before calling bootm to discard the internal dtb which should make barebox fall back to ATAG. Best regards Uwe -- = Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox