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/*
* Discovered on X99-series.
* These platforms have uncore PCI bridges for 4 CPU sockets
* present in ACPI despite having none physically.
*
* Under normal conditions these are disabled depending on
* CPU presence in the socket via Processor Bit Mask (PRBM),
* but on X99 this code is unused or broken as such bridges
* simply do not exist. We fix that by writing 0 to PRBM.
*
* Doing so is important as starting with macOS 11 IOPCIFamily
* will crash as soon as it sees non-existent PCI bridges.
*/
DefinitionBlock ("", "SSDT", 2, "ACDT", "UNC", 0x00000000)
{
External (_SB.UNC0, DeviceObj)
External (PRBM, IntObj)
Scope (_SB.UNC0)
{
Method (_INI, 0, NotSerialized)
{
// In most cases this patch does benefit all operating systems,
// yet on select pre-Windows 10 it may cause issues.
// Remove If (_OSI ("Darwin")) in case you have none.
If (_OSI ("Darwin")) {
PRBM = 0
}
}
}
}