Yocto Linux build system (bitbake) adopts highly sophisticated override syntax using : or _ to efficiently describe what we want to do. This significantly reduce the amount of bb/bbappend code because we do not have to write explicit branching scripts at all in many cases. However, the problem is that key operator character had been changed from _ to : since a version of Yocto distribution. The conversion is available for forward distribution upgrade. But backward one is still not available in official distribution as far as I observed.

デバイスツリーの割り込みノードに3つのセルがある場合それはArm GIC (Generic Interrupt Controller)を用いた割り込みが想定されている。検索で簡単に出ないしよく忘れるので3つのセルそれぞれの意味についてここに書いておく。