ACPI_SIG_DMAR
ACPI_SIG_ASF, ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR,
status = acpi_get_table(ACPI_SIG_DMAR, 0,
status = acpi_get_table(ACPI_SIG_DMAR, 0, &dmar_tbl);