Getting Started With ACPI

# Fixing System Clocks: Manual

# Determining which SSDT you need

  • Note: X99 and X299 see here

Finding which SSDT you need is quite easy actually, first open your decompiled DSDT you got from Dumping the DSDT and Decompiling and Compiling with either MaciASL(if in macOS) or any other text editor if in Windows or Linux(VSCode has an ACPI extension (opens new window) that can also help).

Next search for ACPI000E. You should get something similar:

The above tells us a few things:

  • We in fact do have an AWAC clock
    • If nothing shows up, you don't need to do anything for AWAC or RTC
  • It can be easily disabled with STAS(if not, you can skip to here: RTC0 Method)
    • _STA is the device status, with Zero meaning it won't show up

But to double check, next search for PNP0B00:

And look at that, we can in fact disable our AWAC and enable the RTC! If not skip to here: RTC0 Method

Now it's as simple as grabbing SSDT-AWAC.dsl (opens new window) and compile, no changes needed You can also use the below SSDT to the same effect:

# RTC0 Method

This method is for those who either don't have a PNP0B00 device to re-enable or have no easy way(via STAS variable).

# Finding the ACPI path

Assuming you've gotten your DSDT already opened from earlier, search for the following:

  • Finding the LowPinCount path:
    • Search Name (_ADR, 0x001F0000)
  • Finding the PCI path:
    • Search PNP0A08 (If multiple show up, use the first one)

You should get something like the following show up:

LPC Pathing PCI Pathing

From the above, we can see we have both PCI0 and LPC. Now we can head to the next stage

# Edits to the sample SSDT

Now that we have our ACPI path, lets grab our SSDT and get to work:

By default, this uses PCI0.LPCB for the pathing. you'll want to rename accordingly.

Following the example from above, we'll be renaming it to PCI0.LPC:

Before:

External (_SB_.PCI0.LPCB, DeviceObj) <- Rename this

Scope (_SB.PCI0.LPCB) <- Rename this

Following the example pathing we found, the SSDT should look something like this:

After:

External (_SB_.PCI0.LPC, DeviceObj) <- Renamed

Scope (_SB.PCI0.LPC) <- Renamed

# Compiling the SSDT

With the SSDT done, you're now ready to compile the SSDT!

# Wrapping up

Once you're done making your SSDT, either head to the next page to finish the rest of the SSDTs or head here if you're ready to wrap up:

⟵ Manual HEDT ⟶