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Diffstat (limited to 'Documentation/acpi/uid.md')
| -rw-r--r-- | Documentation/acpi/uid.md | 14 |
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diff --git a/Documentation/acpi/uid.md b/Documentation/acpi/uid.md new file mode 100644 index 000000000000..0354bc52f0c4 --- /dev/null +++ b/Documentation/acpi/uid.md @@ -0,0 +1,14 @@ +# ACPI SSDT \_UID generation + +According to the ACPI spec: + +> The _UID must be unique across all devices with either a common _HID or _CID. + + +When generating SSDTs in coreboot the independent drivers don't know +which \_UID is already in use for a specific \_HID or \_CID. To generate +unique \_UIDs the ACPI device's path is hashed and used as ID. As every ACPI +device has a different path, the hash will be also different for every device. + +Windows 10 verifies all devices with the same \_HID or \_CID and makes +sure that no \_UID is duplicated. If it is it'll BSOD. |