xref: /aosp_15_r20/external/coreboot/Documentation/acpi/uid.md (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1# ACPI SSDT \_UID generation
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3According to the ACPI spec:
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5> The _UID must be unique across all devices with either a common _HID or _CID.
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8When generating SSDTs in coreboot the independent drivers don't know
9which \_UID is already in use for a specific \_HID or \_CID. To generate
10unique \_UIDs the ACPI device's path is hashed and used as ID. As every ACPI
11device has a different path, the hash will be also different for every device.
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13Windows 10 verifies all devices with the same \_HID or \_CID and makes
14sure that no \_UID is duplicated. If it is it'll BSOD.
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