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I'm having the same problem as here: viewtopic.php?f=1&t=30288

I found that if I pack the XSDT structure header and set the alignment of the following 64-bit pointers to 4 rather than the default 8, then I get the correct 64-bit pointer values to read the pointed-to tables (so table entry 0 is at offset 36 rather than 40 from the beginning of the XSDT).

With a quick google search, https://github.com/tianocore/edk2/blob/ ... Protocol.c seems to corroborate that the XSDT pointers are indeed not aligned to 8-byte boundaries.

I tried to follow the ACPI spec link on https://wiki.osdev.org/XSDT but that appears to be dead.

Is it known that these pointers are not 8-byte aligned? If so, can https://wiki.osdev.org/XSDT be updated to clarify this? I don't have edit permissions for the wiki.

The ACPI spec is here now.


I just checked the ACPI spec, and yes, that's what it says.


You can give yourself edit permissions.

Thank you for the confirmation as well as the updated ACPI specification link and note about the wiki. I have joined the wiki group and updated the XSDT page with the updated ACPI specification link and a note about the pointer alignment.