You may have seen something like this in one of your ACPI tables:
Store ("Some text", Debug)
And you may wonder what you need to do to see the debug messages at startup. Well. That is easier than you might expect. And no. You don’t need to install anything. Just add this to: /Library/Preferences/SystemConfiguration/com.apple.Boot.plist
-v debug=0x12a acpi_layer=0x08 acpi_level=0x02
The number one reason for telling you this is that it enables you to check what ACPI Methods in the processor scopes are being called/evaluated.
I did the same and here I only see the debug messages for the following ACPI Methods in the processor scopes: _INI, _PDC, APSS, ACST and _DSM. The latter of course only for CPU0 on Ivy Bridge and Haswell configurations, where we inject a ‘plugin-type’ property, set to 1, to trigger the load of the required plugins. And thus, all other methods in power management related ACPI tables is cruft and can be removed/forgotten.
Oh and here is another tip. The output may scroll too fast, as it did here, but you can stop it by adding Sleep (10000) in the last Processor Scope. This way it waits for 10 seconds before continuing. I also use my iPhone/iPad to film the output.
Note: I am aware of other tools that dump the debug messages, but I love to share anything that may help us. This may not be the best solution for you, but this is what I use today.
Download debugMachKernel.sh and change your boot arguments to:
-v debug=0x12a acpi_layer=0x08 acpi_level=0x02 msgbuf=309212
Reboot and the debug output can be found in:
/var/log/system.log or use:
sudo dmesg | grep ACPI.
With macOS Sierra we only need:
debug=0x12a acpi_layer=0x08 acpi_level=0x02
Reboot and enter:
log show --predicate 'process == "kernel"' --debug --last "5m"
This is everything that you need to do.