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authorBob Moore <robert.moore@intel.com>2009-03-13 09:10:46 +0800
committerLen Brown <len.brown@intel.com>2009-03-27 12:11:03 -0400
commit20869dcfde204e1c21b642608d708d82472fee2b (patch)
treea3e6dca8ff835def8ba6a41606aa30cac5d9fa1c /drivers/acpi/acpica/hwregs.c
parent8636f8d257b3edf5a1529df93119cdc630ed85c7 (diff)
downloadtalos-obmc-linux-20869dcfde204e1c21b642608d708d82472fee2b.tar.gz
talos-obmc-linux-20869dcfde204e1c21b642608d708d82472fee2b.zip
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>
Diffstat (limited to 'drivers/acpi/acpica/hwregs.c')
-rw-r--r--drivers/acpi/acpica/hwregs.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index fd7abe277db3..611736266f9f 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -328,6 +328,21 @@ acpi_status acpi_hw_register_write(u32 register_id, u32 value)
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;
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