I just noticed the project Laptop-DSDT-Patch, by RehabMan. It contains “Common DSDT patches for Ivy/Sandy/Haswell laptops for running OS X“, so it’s for ‘hackintosh’ hackers using non-Apple hardware to run Apple’s OS, OS X, and have to deal with non-Apple hardware/firmware, particularly ACPI’s DSDT table, a nice example of how the modding community generates some interesting firmware tools, if nothing else.
Quoting from from the beginning of RehabMan’s HP-ProBook-4x30s wiki on How to patch your DSDT (useful background even if you don’t this HP model):
Although there are pre-patched DSDTs available as downloads from the tonymacx86.com forums and in installer packages such as the HP ProBook Installer, there can be differences in individual DSDTs that can cause delays in booting and perhaps other problems. Perhaps there are slight differences in BIOS settings, memory installed, etc, that is causing these differences. It is best, therefore, to patch your own DSDT and install it into /Extra/dsdt.aml (Chameleon) or EFI/Clover/ACPI/patched (Clover). I have included five different methods for extracting your native DSDT. Just pick the method that seems easiest for you. The easiest one will depend on whether you still have Windows installed, whether you already have a Linux USB stick prepared, and just how familiar you are with both systems.
Quoting from the OSx86 wiki, for the Mac OSX-perspective on it, ACPI’s DSDT is:
The Differentiated System Description Table is the main table in the ACPI part of a computer’s BIOS. The Advanced Configuration and Power Interface (ACPI) defines a large number of tables that provide the interface between an ACPI-compliant operating system and system firmware. These allow description of system hardware in a platform-independent manner in ACPI Machine Language (AML). The problem is that OS X has an incomplete ACPI implementation which supports only a subset of DSDT. Modifying the DSDT allows the user to better support their hardware. For example, fixing Time Machine and the UUID 35 error is possible after modifying the DSDT. To patch your DSDT, you must either use a new table file that someone else has provided, or extract and modify your own. Then tell your bootloader to use the new DSDT file instead of the BIOS. On a few motherboards it is also possible to replace the BIOS with an updated BIOS with a patched DSDT. One of the simplest ways to extract your DSDT from your BIOS is by using DSDT Editor. Once you have downloaded DSDT Editor, open it and press File –> Extract DSDT. After 2-15 seconds, your DSDT should appear on the screen.
Look at the various ACPI-centric projects RepoMan has, there’re many! Also, the Ubuntu wiki and SmackerelOfOpinion blog are both excellent for ACPI diagnostic tips.
These ‘modding community’-based ACPI changes for OS X are educational, to see how people can extend their purchases for use cases beyond those that the vendor could imagine. As systems get more tamper-proof, it seems likely that users will have less and less ability to change things. [There also exists a HUGE modding community by photographers and their smartcameras (embedded devices). They add amazing new features. The other day I saw one talk about how they update the system to be able to take pictures of lighting better. Nice example of how owners can add features to their purchases, if able to update their firmware. 🙂 And of course there is custom ‘firmware’ for smartphones, entire distros.]
Personal modding hobbies aside, how much time, if any, do enterprise sysadmins currently spend fixing OEM ACPI tables and other firmware features, to make their systems work properly?