# Fixing Backlight: Manual | Getting Started With ACPI

# # Fixing Backlight: Manual

- Finding the ACPI path
- Edits to the sample SSDT
- Compiling the SSDT
- Wrapping up

## # Finding the ACPI path

For this guide, we're gonna assume Windows is already on this laptop, as otherwise creating this SSDT is a bit more difficult.

Now open DeviceManager, and head to the following:

    Device Manager -> Display Adapters -> Properties -> Details > BIOS device name

- Note some GPU ACPI pathing may be hiding under "BIOS device name"

From the above example, we can see our display is hooked up to `PCI0.GFX0`

## # Edits to the sample SSDT

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

- SSDT-PNLF.dsl
  (opens new window)
- SSDT-PNLF-CFL.dsl
  (opens new window)
  - For Coffee Lake and newer

By default, this uses `PCI0.GFX0` for the pathing. you'll want to rename accordingly. For this example, we'll assume your pathing is `PCI0.GPU0`:

Before:

    External (_SB_.PCI0.GFX0, DeviceObj) <- Rename this

    Scope (_SB.PCI0.GFX0) <- Rename this

    Device(_SB.PCI0.GFX0.PNLF) <- Rename this

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

After:

    External (_SB_.PCI0.GPU0, DeviceObj) <- Renamed

    Scope (_SB.PCI0.GPU0) <- Renamed

    Device(_SB.PCI0.GPU0.PNLF) <- 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:

- Cleanup