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109 lines
3.7 KiB
Markdown
109 lines
3.7 KiB
Markdown
# Fixing System Clocks on HEDT: Manual
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* [Finding the ACPI path](#finding-the-acpi-path)
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* [Edits to the sample SSDT](#edits-to-the-sample-ssdt)
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* [Compiling the SSDT](#compiling-the-ssdt)
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* [Wrapping up](#wrapping-up)
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## Seeing if you need SSDT-RTC0-RANGE
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To start, 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).
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Now search for `PNP0B00` and look at the `_CRS` entry within it:
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And from the above example, we see we have 2 banks of RTC memory:
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* Bank 1: starts at 0x70 and is length 0x2
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* Bank 2: starts at 0x74 and is length 0x4
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Now the problem is that the OEM forgot to mat sections 0x72 and 0x73. Because of this, macOS may halt while booting(prominently in Big Sur)
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And finally, verify if it has an _STA method as well. This will be used shortly
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## Finding the ACPI path
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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).
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To start, search for the following:
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* Finding the RTC name:
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* Search `PNP0B00`
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* Finding the LowPinCount path:
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* Search `Name (_ADR, 0x001F0000)`
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* Finding the PCI path:
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* Search `PNP0A08` (If multiple show up, use the first one)
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You should get something like the following show up:
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RTC Pathing | LPC Pathing | PCI Pathing
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:----------:|:-------------------------:|:-------------------------:
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 |  | 
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From the above, we can see we have `RTC`, `LPC0` and `PCI0`. Now we can head to the next stage
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## Edits to the sample SSDT
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Now that we have our ACPI path, lets grab our SSDT and get to work:
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* [SSDT-RTC0-RANGE.dsl](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-RTC0-RANGE.dsl)
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By default, this uses `PC00.LPC0.RTC` for the pathing. you'll want to rename accordingly.
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Following the example from above, we'll be renaming it to `PCI0.LPC0.RTC`:
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**Before**:
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```
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External (_SB_.PC00.LPC0, DeviceObj) <- Rename this
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External (_SB_.PC00.LPC0.RTC_, DeviceObj) <- Rename this
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Scope (_SB.PC00.LPC0) <- Rename this
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```
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Following the example pathing we found, the SSDT should look something like this:
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**After**:
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```
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External (_SB_.PCI0.LPC0, DeviceObj) <- Renamed
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Scope (_SB.PCI0.LPC0.RTC) <- Renamed
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Scope (_SB.PCI0.LPC0) <- Renamed
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/* <- Remove if your RTC device didn't have an _STA
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Scope (RTC)
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{
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Method (_STA, 0, NotSerialized) // _STA: Status
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{
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If (_OSI ("Darwin"))
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{
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Return (Zero)
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}
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Else
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{
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Return (0x0F)
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}
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}
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}
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*/ <- Remove if your RTC device didn't have an _STA
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```
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### Compiling the SSDT
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With the SSDT done, you're now [ready to compile the SSDT!](/Manual/compile.md)
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## Wrapping up
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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:
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* [**Cleanup**](/cleanup.md)
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