diff options
Diffstat (limited to 'drivers/acpi/processor_core.c')
| -rw-r--r-- | drivers/acpi/processor_core.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 76156ac91bd3..d56a439ac614 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -256,6 +256,43 @@ acpi_processor_errata ( /* -------------------------------------------------------------------------- + Common ACPI processor fucntions + -------------------------------------------------------------------------- */ + +/* + * _PDC is required for a BIOS-OS handshake for most of the newer + * ACPI processor features. + */ + +int acpi_processor_set_pdc(struct acpi_processor *pr, + struct acpi_object_list *pdc_in) +{ + acpi_status status = AE_OK; + u32 arg0_buf[3]; + union acpi_object arg0 = {ACPI_TYPE_BUFFER}; + struct acpi_object_list no_object = {1, &arg0}; + struct acpi_object_list *pdc; + + ACPI_FUNCTION_TRACE("acpi_processor_set_pdc"); + + arg0.buffer.length = 12; + arg0.buffer.pointer = (u8 *) arg0_buf; + arg0_buf[0] = ACPI_PDC_REVISION_ID; + arg0_buf[1] = 0; + arg0_buf[2] = 0; + + pdc = (pdc_in) ? pdc_in : &no_object; + + status = acpi_evaluate_object(pr->handle, "_PDC", pdc, NULL); + + if ((ACPI_FAILURE(status)) && (pdc_in)) + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Error evaluating _PDC, using legacy perf. control...\n")); + + return_VALUE(status); +} + + +/* -------------------------------------------------------------------------- FS Interface (/proc) -------------------------------------------------------------------------- */ |