# Fixing Trackpads: Manual

* [Finding the ACPI path](#finding-the-acpi-path)
* [Edits to the sample SSDT](#edits-to-the-sample-ssdt)
* [Compiling the SSDT](#compiling-the-ssdt)
* [Wrapping up](#wrapping-up)


## Finding the ACPI path

Finding the ACPI pathing is quite easy actually, first open your decompiled DSDT you got from [Dumping the DSDT](/Manual/dump.md) and [Decompiling and Compiling](/Manual/compile.md) with either maciASL(if in macOS) or any other text editor if in Windows or Linux(VSCode has an [ACPI extension](https://marketplace.visualstudio.com/items?itemName=Thog.vscode-asl) that can also help).

Next search for `Device (GPI0)`. Should give you a result similar to this:

![](../../images/Laptops/trackpad-md/gpi0.png)

What we care about from this is the `_STA` method:

```
Method (_STA, 0, NotSerialized)
{
    If ((GPHD == One))
    {
        Return (0x03)
    }

    Return (0x0F)
}
```

What we want is for this to always return `0x0F` when booting macOS, so we want to make an SSDT that will return `GPHD == Zero` in macOS.

**NOTE that you may have the other way around where GPHD needs to be set as `One` to return `0x0F`**. And your device name may also be different, don't throw random SSDTs in thinking it'll work

Here's some more examples:

![](../../images/Laptops/trackpad-md/gpi0-2.png)

With this example, we can see that we need both `SBRG` and `GPEN` to return `One`. If only one is present, it'll create some issues so in our SSDT we'll want to have both of them return `One`:


## Edits to the sample SSDT

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

* [SSDT-GPI0.dsl](https://github.com/dortania/Getting-Started-With-ACPI/blob/master/extra-files/decompiled/SSDT-GPI0.dsl)

From the second example, we'll want to set both GPEN and SBRG to `One` to allow it to operate in macOS:

**Before**:

```
If (_OSI ("Darwin"))
        {
            GPEN = One <- Change to the right variables
            SBRG = One <- Change to the right variables
	}
```

![](../../images/Laptops/trackpad-md/ssdt-before.png)

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

**After**:

```
If (_OSI ("Darwin"))
        {
            GPEN = One <- Proper variables
        }
```

![](../../images/Laptops/trackpad-md/ssdt-after.png)

## Compiling the SSDT

 With the SSDT done, you're now [ready to compile the SSDT!](/Manual/compile.md)

## 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**](/cleanup.md)