diff options
| author | Len Brown <lenb@kernel.org> | 2007-04-28 20:37:26 -0400 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2007-05-23 14:32:41 -0700 |
| commit | 27c99eb74744c71c162b68d5b3ed7c682eb55e3e (patch) | |
| tree | e2cd92374d5c08803e46bc5d26f89653ff495522 /drivers | |
| parent | cf24f1a9770cb6ea804e8068cc252d2f9f35e393 (diff) | |
[PATCH] ACPI: Fix 2.6.21 boot regression on P4/HT
Up through 2.6.20 we cleared the FADT.CSTATE_CONTROL field
for FADT versions before r3, because it made no sense
for that reserved field to be set for pre-ACPI 2.0 systems.
It turns out that not clearing this field exposes
Linux to SMM BIOS failures, so do the same in 2.6.21.
http://bugzilla.kernel.org/show_bug.cgi?id=8346
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Diffstat (limited to 'drivers')
| -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; + } + } /****************************************************************************** |