On Wed, Apr 15, 2015 at 11:22 AM, Nikolay Dimitrov <picmas...@mail.bg> wrote: > Hi Bruce, > > > On 04/15/2015 04:13 PM, Bruce Ashfield wrote: >> >> On 2015-04-15 08:33 AM, Bach, Pascal wrote: >>> >>> Hi >>> >> >> Adding oe-core, since that's the right place to have a discussion >> like this. >> >>> As ARM now also moved to device tree it look like in future we will >>> have more kernels that are using device tree then ones that are >>> not. >> >> >> True, but it has been like this for quite some time now :) >> >>> As far as I understand currently the generation of device trees is >>> controlled via KERNEL_DEVICETREE and is handled in via an include >>> file recipes-kernel/linux/linux-dtb.inc. >>> >>> I was thinking about moving this include into a class so it becomes >>> easier to use. Before I dive into implementing something I would >>> like some feedback from the community. >> >> >> The big trick with changing anything like this is compatibility with >> existing recipes. Whatever we do, existing recipes and layers >> shouldn't be broken .. or if they are broken, there should be a >> compelling technical reason to do so. >> >>> >>> I have the following variant in mind. >>> >>> Add the device tree generation to the current kernel.bbclass (or >>> let kernel.bblcass inherit from a kernel-dtb.bbclass). This way all >>> kernels would automatically be DT enabled. The class would check if >>> KERNEL_DEVICETREE is set and generate device trees based on this >>> information. For boards that don't have KERNEL_DEVICETREE set the >>> class would do nothing and the behavior is like before. The >>> advantage I see with this approach is that the only thing a user >>> needs to do is to set KERNEL_DEVICETREE in the board and make sure >>> the device trees are available in the kernel they like to build. >> >> >> That's pretty much the experience that most users have now, since >> there's nearly always a kernel recipe created, that recipe includes >> linux-dtb.inc, and sets KERNEL_DEVICETREE. > > > As far as I understood, Pascal's idea is to remove the need for user > recipes to include linux-dtb.inc, and provide this functionality via > inheritance.
That is obvious. My questions are around "why". There's no big technical advantage, and if you remove that existing file, you break existing recipes. Which means you need to leave a stub in place. So without a technical advantage, it's churn for the sake of churn. Bruce > >> Everything else happens to build and package the device tree. >> >> Was there something specifically that was causing issues with the >> current way of building them ? >> >> Cheers, >> >> Bruce >> >>> >>> I appreciate your feedback? >>> >>> Regards Pascal >>> >> > > Regards, > Nikolay > > -- > _______________________________________________ > yocto mailing list > yocto@yoctoproject.org > https://lists.yoctoproject.org/listinfo/yocto -- "Thou shalt not follow the NULL pointer, for chaos and madness await thee at its end" -- _______________________________________________ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
