Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=79fff270026dc46634563a29b99e4034028ee919
Commit: 79fff270026dc46634563a29b99e4034028ee919
Parent: de46c33745f5e2ad594c72f2cf5f490861b16ce1
Author: Bob Moore <[EMAIL PROTECTED]>
AuthorDate: Sat Apr 28 20:53:50 2007 -0400
Committer: Len Brown <[EMAIL PROTECTED]>
CommitDate: Sat Apr 28 20:55:06 2007 -0400
ACPICA: clear fields reserved before FADT r3
Linux-2.6.21 stopped booting on a P4/HT because Linux
wrote the FADT.CST_CNT value to the SMI_CMD.
Apparently this stumbled over some SMM instability,
such as confusing SMM when invoking it from cpu1.
Linux did this because even though the r2 FADT reserves
the CST_CNT field, this BIOS set that field and Linux
used it.
Turns out that up through 2.6.20 we explicitly cleared
cst_control for r2 FADTs. So here we go back to doing that,
plus also clear some additional fields that are reserved
until FADT r3.
http://bugzilla.kernel.org/show_bug.cgi?id=8346
Signed-off-by: Bob Moore <[EMAIL PROTECTED]>
Signed-off-by: Len Brown <[EMAIL PROTECTED]>
---
drivers/acpi/tables/tbfadt.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/acpi/tables/tbfadt.c b/drivers/acpi/tables/tbfadt.c
index 807c711..1db833e 100644
--- a/drivers/acpi/tables/tbfadt.c
+++ b/drivers/acpi/tables/tbfadt.c
@@ -347,6 +347,18 @@ static void acpi_tb_convert_fadt(void)
acpi_gbl_xpm1b_enable.space_id =
acpi_gbl_FADT.xpm1a_event_block.space_id;
}
+
+ /*
+ * For ACPI 1.0 FADTs, ensure that reserved fields (which should be
zero)
+ * are indeed zero. This will workaround BIOSs that inadvertently placed
+ * values in these fields.
+ */
+ if (acpi_gbl_FADT.header.revision < 3) {
+ acpi_gbl_FADT.preferred_profile = 0;
+ acpi_gbl_FADT.pstate_control = 0;
+ acpi_gbl_FADT.cst_control = 0;
+ acpi_gbl_FADT.boot_flags = 0;
+ }
}
/******************************************************************************
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