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authorBob Moore <robert.moore@intel.com>2011-02-14 15:50:42 +0800
committerLen Brown <len.brown@intel.com>2011-03-02 19:38:03 -0500
commit64b3db22c04586997ab4be46dd5a5b99f8a2d390 (patch)
treee0642436efe91c824d84383cba3e8fc906c4a2d0 /drivers/acpi/acpica
parent6dfad339645247c9deb553e4d68e21211ddc61bd (diff)
ACPICA: Remove use of unreliable FADT revision field
The revision number in the FADT has been found to be completely unreliable and cannot be trusted. Only the table length can be used to infer the actual version. Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/acpica')
-rw-r--r--drivers/acpi/acpica/tbfadt.c5
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;