diff options
| author | Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | 2005-10-23 16:31:00 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2005-12-01 01:30:35 -0500 |
| commit | 05131ecc99ea9da7f45ba3058fe8a2c1d0ceeab8 (patch) | |
| tree | dec76975406874cf677d6391302f42a6da55ac38 /drivers/acpi/processor_core.c | |
| parent | d2149b542382bfc206cb28485108f6470c979566 (diff) | |
| download | linux-05131ecc99ea9da7f45ba3058fe8a2c1d0ceeab8.tar.gz | |
[ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once
Linux invokes the AML _PDC method (Processor Driver Capabilities)
to tell the BIOS what features it can handle. While the ACPI
spec says nothing about the OS invoking _PDC multiple times,
doing so with changing bits seems to hopelessly confuse the BIOS
on multiple platforms up to and including crashing the system.
Factor out the _PDC invocation so Linux invokes it only once.
http://bugzilla.kernel.org/show_bug.cgi?id=5483
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/processor_core.c')
| -rw-r--r-- | drivers/acpi/processor_core.c | 28 |
1 files changed, 11 insertions, 17 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 4217925626423..66bbda78507a3 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -253,31 +253,21 @@ static int acpi_processor_errata(struct acpi_processor *pr) * _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) +static int acpi_processor_set_pdc(struct acpi_processor *pr) { + struct acpi_object_list *pdc_in = pr->pdc; 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; + if (!pdc_in) + return_VALUE(status); - status = acpi_evaluate_object(pr->handle, "_PDC", pdc, NULL); + status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL); - if ((ACPI_FAILURE(status)) && (pdc_in)) + if (ACPI_FAILURE(status)) ACPI_DEBUG_PRINT((ACPI_DB_INFO, - "Error evaluating _PDC, using legacy perf. control...\n")); + "Could not evaluate _PDC, using legacy perf. control...\n")); return_VALUE(status); } @@ -574,6 +564,10 @@ static int acpi_processor_start(struct acpi_device *device) "Error installing device notify handler\n")); } + /* _PDC call should be done before doing anything else (if reqd.). */ + arch_acpi_processor_init_pdc(pr); + acpi_processor_set_pdc(pr); + acpi_processor_power_init(pr, device); if (pr->flags.throttling) { |