15 lines
566 B
Markdown
15 lines
566 B
Markdown
|
# 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.
|