diff options
| -rw-r--r-- | drivers/acpi/tables/tbfadt.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/acpi/tables/tbfadt.c b/drivers/acpi/tables/tbfadt.c index 807c7116e94b..d34149140d86 100644 --- a/drivers/acpi/tables/tbfadt.c +++ b/drivers/acpi/tables/tbfadt.c @@ -347,6 +347,20 @@ static void acpi_tb_convert_fadt(void) acpi_gbl_xpm1b_enable.space_id = acpi_gbl_FADT.xpm1a_event_block.space_id; } + /* + * _CST object and C States change notification start with + * ACPI 2.0 (FADT r3). Although the field should be Reserved + * and 0 before then, some pre-r3 FADT set this field and + * it results in SMM-related boot failures. For them, clear it. + */ + if ((acpi_gbl_FADT.header.revision < 3) && + (acpi_gbl_FADT.cst_control != 0)) { + ACPI_WARNING((AE_INFO, + "Ignoring BIOS FADT r%u C-state control", + acpi_gbl_FADT.header.revision)); + acpi_gbl_FADT.cst_control = 0; + } + } /****************************************************************************** |