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authorVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>2005-10-23 16:31:00 -0400
committerLen Brown <len.brown@intel.com>2005-12-01 01:30:35 -0500
commit05131ecc99ea9da7f45ba3058fe8a2c1d0ceeab8 (patch)
treedec76975406874cf677d6391302f42a6da55ac38 /drivers
parentd2149b542382bfc206cb28485108f6470c979566 (diff)
[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')
-rw-r--r--drivers/acpi/processor_core.c28
-rw-r--r--drivers/acpi/processor_idle.c2
-rw-r--r--drivers/acpi/processor_perflib.c2
3 files changed, 11 insertions, 21 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 42179256264..66bbda78507 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) {
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 70d8a6ec092..1915c377bfc 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1014,8 +1014,6 @@ int acpi_processor_power_init(struct acpi_processor *pr,
}
}
- acpi_processor_power_init_pdc(&(pr->power), pr->id);
- acpi_processor_set_pdc(pr, pr->power.pdc);
acpi_processor_get_power_info(pr);
/*
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 22c7bb66c20..532370734c6 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -315,8 +315,6 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr)
if (!pr || !pr->performance || !pr->handle)
return_VALUE(-EINVAL);
- acpi_processor_set_pdc(pr, pr->performance->pdc);
-
status = acpi_get_handle(pr->handle, "_PCT", &handle);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,