The Hot Mess of Closed Source

In the course of trying to track down a regression, Akihiro Suda traced the problem to a couple of patches that had been accepted into a recent kernel release. A regression is when something stops working and the developers have to look back at the patch history to see which one caused the breakage. Identifying regressions is what the Git bisect command is for. It starts from a known good version and a known bad version, tests the middle version, and then just keeps going to the next middle version until it finds the bad patch that started it all. Git makes regressions fun.

However, this particular regression had to do with running virtualized systems and related to both Advanced Configuration and Power Interface Component Architecture (ACPICA), which is for discovering and configuring the hardware on a given system, and EFISTUB, which lets the (Unified Extensible Firmware Interface) UEFI load the Linux kernel as an EFI application.

The keyword is "firmware." Generally this is closed source software associated with a specific piece of hardware, without which the hardware won't run at all. Linux tolerates it because it has no choice, but as with the Basic Input/Output System (BIOS), firmware is generally always a broken, buggy pain in the butt. Sometimes developers will reverse engineer the firmware and write their open source version, but generally the closed source hot mess is what we get.

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