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48 lines
3.1 KiB
Markdown
48 lines
3.1 KiB
Markdown
# Fixing System Clocks
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**For Intel 300 series chipsets and newer**, this also includes X299 refreshes and Icelake laptops. Common machines:
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* X299X (10th Gen refresh)
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* B360
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* B365
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* H310
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* H370
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* Z370 (Gigabtye and AsRock boards with newer BIOS versions)
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* Z390
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* 400 series (Cometlake)
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* 495 series (Icelake)
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So on newer Intel 300 series motherboards, manufactueres started pushing for a new type of system clock: **AWAC**( **A** **W**eird **A**ss **C**lock). One small problem, macOS doesn't know what the hell an AWAC clock is instead only familiar with the legacy **RTC**(**R**eal **T**ime **C**lock). So we need to figure out how to bring back the old clock, thats where `SSDT-AWAC` and `SSDT-RTC0` come in:
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* [SSDT-AWAC](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-AWAC.dsl)
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* Disables AWAC and enables RTC
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* In your DSDT, there's a varaible called `STAS` used for holding either a `One` or `Zero` to determine which clock to use(`One` for RTC and `Zero` for AWAC)
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* [SSDT-RTC0](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-RTC0.dsl)
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* Used for creating a fake RTC device for macOS to play with
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* In very rare circumstances, some DSDTs may not have a legacy RTC to fall back on. When this happens, we'll want to create a fake device to make macOS happy
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Note: AWAC actually stands for ACPI Wake Alarm Counter/Clock for those curious, though I'll forever know it as A Weird Ass Clock ;p
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## Determining which SSDT you need
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To determine whether you need [SSDT-AWAC](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-AWAC.dsl) or [SSDT-RTC0](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-RTC0.dsl):
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* open your decompiled DSDT and search for `Device (AWAC)`
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* If **nothing shows up** then no need to continue and **no need for this SSDT** as you have no AWAC. **Otherwise, continue on!**
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* If you get a result then you have an `AWAC` system clock present, then continue with the **next search for `STAS ==`**:
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As you can see we found the `STAS ==` in our DSDT, this means we're able to force enable our Legacy RTC. In this case, [SSDT-AWAC](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-AWAC.dsl) will be used As-Is with no modifications required. Just need to compile. Note that `STAS` may be found in AWAC first instead of RTC like in our example, this is normal.
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For systems where **no `STAS`** shows up **but** you do have `AWAC`, you can use [SSDT-RTC0](https://github.com/acidanthera/OpenCorePkg/blob/master/Docs/AcpiSamples/SSDT-RTC0.dsl) though you will need to check the naming of LPC in your DSDT
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By default the SSDT uses `LPCB`, you can check what your system uses by just searching for `Name (_ADR, 0x001F0000)`. This address is used for Low Pin Count devices(LPC) but the device name can vary between `LPCB`, `LBC` or `LBC0`:
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## [Now you're ready to compile the SSDT!](/Manual/compile.md)
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