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Yocto: BitBake and Dependencies - e.g. One recipe to use output of another recipe

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It feels weird to help some get their working build to fail and then for them to be happy about it... (RP) Introduction This work is sponsored by Reliable Embedded Systems . You can find more information about our training/consulting services here . Objectives The goal of this blog post is to look into BitBake dependencies. As an example let's take recipe A ( u-boot-phytex-imx ) which needs the output of recipe B ( firmware-imx-8m ) for a successful compilation. (Please don't ask why.) To be more precise here is an excerpt of recipe A ( u-boot-phytex-imx ): # --> this funny u-boot from Phytec needs the ddr_firmware binaries in ${S} # Note: here we copy deployed stuff from another recipe # to the source dir of this recipe! # # DEPENDS deals with build-time depenencies # Read my blog post to find out why DEPENDS does not work here # # DEPENDS += " \ # firmware-imx-8m \ # " # RDEPENDS is wrong anyhow for what I want ...
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Yocto: kernel modules not showing up in the rootfs

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Introduction This work is sponsored by Reliable Embedded Systems . You can find more information about our training/consulting services here . Objectives The goal of this blog post is to point out a well known and documented issue with kernel modules not ending up on the root file system which is likely overseen by people until they stumble over it.   Kernel module(s) So you created a brand new kernel module, or you just wanted to include all the kernel modules in the root file system, or just one of them. You reach out to the community mailing list or chat with something like this: I have MACHINE_EXTRA_RRECOMMENDS + = "kernel-modules" in my machine configuration. When I look into the rootfs I see no modules installed in /lib/modules/ $( uname -r ) . I get only a modules tarball in the deploy directory. I also tried MACHINE_EXTRA_RDEPENDS + = "kernel-modules" and it still does not work. What am I doing wrong? Check the Mega Manual If things d...
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Compiler tunes benchmarks with the Yocto Project

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Introduction This work is sponsored by Reliable Embedded Systems . You can find more information about our training/consulting services here . Objectives The goal of this blog post is to look at the mystery of compiler tunes. Since I'm a non believer in micro optimizations I will try to run some benchmarks with different compiler tunes and let them run on the same boards natively as well as inside a docker container. Since I have plenty of i.mx6 quad core boards I will use them for most of the tests. I might run a few tests on other boards as well. We'll only look at CPU/calculations for now and will try to answer a few questions like: What's the difference between armv7a soft float and armv7a hard float? What's the difference between armv7a hard float and code optimized for a cortexa9 hard float? What's the difference between different machines in general - ignoring the compiler tunes? Does code with the same compiler tunes run slower on the native host...
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