1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index 428d44e2d162..6f5588e62c0a 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -384,8 +384,11 @@ static void acpi_tb_convert_fadt(void)
          *
          * The ACPI 1.0 reserved fields that will be zeroed are the bytes located at
          * offset 45, 55, 95, and the word located at offset 109, 110.
+         *
+         * Note: The FADT revision value is unreliable. Only the length can be
+         * trusted.
          */
-        if (acpi_gbl_FADT.header.revision < FADT2_REVISION_ID) {
+        if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) {
                 acpi_gbl_FADT.preferred_profile = 0;
                 acpi_gbl_FADT.pstate_control = 0;
                 acpi_gbl_FADT.cst_control = 0;