diff options
Diffstat (limited to 'drivers/acpi/acpica/hwregs.c')
| -rw-r--r-- | drivers/acpi/acpica/hwregs.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c index fd7abe277db..611736266f9 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; |