ACPICA: Preserve all PM control reserved and ignored bits
As per the ACPI specification, preserve (read/modify/write) all
bits that are defined as either reserved or ignored (PM control
control registers only.)
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>
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index fd7abe2..6117362 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -328,6 +328,21 @@
case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
+ /*
+ * For control registers, all reserved bits must be preserved,
+ * as per the ACPI spec.
+ */
+ status =
+ acpi_read(&read_value, &acpi_gbl_FADT.xpm2_control_block);
+ if (ACPI_FAILURE(status)) {
+ goto exit;
+ }
+
+ /* Insert the bits to be preserved */
+
+ ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
+ read_value);
+
status = acpi_write(value, &acpi_gbl_FADT.xpm2_control_block);
break;