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bb.utils.contains yocto

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bb.utils.contains  is most commonly used function in Yocto. grep in poky directory returned with 696 count. $ grep -nr 'bb.utils.contains' poky/ | wc -l 696 It's definition is present in 'poky/bitbake/lib/bb/utils.py' file This function returns third argument if the second argument is subset of the first argument else returns fourth argument Let's take an example to understand this. You can see from the above screenshot, when the second argument is a subset of first argument, "present" was returned, else "notpresent" was returned We can also use bb.utils.contains inside if loop. This we can use inside a recipe. if ${@bb.utils.contains('SOMEFLAG','NEWVALUE3','true','false',d)}; then     FOO = 'HELLO' fi
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make config vs oldconfig vs defconfig vs menuconfig vs savedefconfig

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Building the Linux Kernel is a two-step process: Configuring the Kernel options Building the Kernel with those options. There are many methods available for configuring the kernel. make config: Text-based Configuration.  Options are prompted one after another. All options need to be answered Access to former options is not possible make menuconfig: Menu-driven user interface Allows to navigate forwards and backward directly between features Allows to load and save files with filenames different from ".config" Provides search feature It uses ncurses library for GUI. If the ncurses library is not installed, make menuconfig option fails. To install ncurses library on Ubuntu: sudo apt-get install libncurses5-dev make defconfig: Creates a ".config" file with default options from the ARCH supplied defconfig Configurations are generally stored in the directory: arch/$(ARCH)/configs $ ls arch/x86/configs/ i386_defconfi...
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vermagic in Linux Device Driver

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Vermagic is a magic string present in the Linux Kernel and added into the .modinfo section of the Linux Kernel Modules. This is used to verify whether the kernel module was compiled for the particular kernel version or not. ‘VERMAGIC_STRING’ is generated by the kernel configuration. #define VERMAGIC_STRING                         \     UTS_RELEASE " "                         \     MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT             \     MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_MODVERSIONS   \     MODULE_ARCH_VERMAGIC                        \     MODULE_RANDSTRUCT_PLUGIN Code: Output: If we change the value of 'vermagic' string using 'MODULE_INFO', we will get the error while lo...
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