[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>

1 files changed, 0 insertions, 51 deletions

diff --git a/arch/ia64/kernel/cpufreq/acpi-cpufreq.c b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
index da4d5cf80a48..5a1bf815282d 100644
--- a/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
+++ b/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
@@ -269,48 +269,6 @@ acpi_cpufreq_verify (
 }
 
 
-/*
- * processor_init_pdc - let BIOS know about the SMP capabilities
- * of this driver
- * @perf: processor-specific acpi_io_data struct
- * @cpu: CPU being initialized
- *
- * To avoid issues with legacy OSes, some BIOSes require to be informed of
- * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
- * accordingly. Actual call to _PDC is done in driver/acpi/processor.c
- */
-static void
-processor_init_pdc (
-		struct acpi_processor_performance *perf,
-		unsigned int cpu,
-		struct acpi_object_list *obj_list
-		)
-{
-	union acpi_object *obj;
-	u32 *buf;
-
-	dprintk("processor_init_pdc\n");
-
-	perf->pdc = NULL;
-	/* Initialize pdc. It will be used later. */
-	if (!obj_list)
-		return;
-
-	if (!(obj_list->count && obj_list->pointer))
-		return;
-
-	obj = obj_list->pointer;
-	if ((obj->buffer.length == 12) && obj->buffer.pointer) {
-		buf = (u32 *)obj->buffer.pointer;
-       		buf[0] = ACPI_PDC_REVISION_ID;
-       		buf[1] = 1;
-       		buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
-		perf->pdc = obj_list;
-	}
-	return;
-}
-
-
 static int
 acpi_cpufreq_cpu_init (
 	struct cpufreq_policy   *policy)
@@ -320,14 +278,7 @@ acpi_cpufreq_cpu_init (
 	struct cpufreq_acpi_io	*data;
 	unsigned int		result = 0;
 
-	union acpi_object		arg0 = {ACPI_TYPE_BUFFER};
-	u32				arg0_buf[3];
-	struct acpi_object_list 	arg_list = {1, &arg0};
-
 	dprintk("acpi_cpufreq_cpu_init\n");
-	/* setup arg_list for _PDC settings */
-        arg0.buffer.length = 12;
-        arg0.buffer.pointer = (u8 *) arg0_buf;
 
 	data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 	if (!data)
@@ -337,9 +288,7 @@ acpi_cpufreq_cpu_init (
 
 	acpi_io_data[cpu] = data;
 
-	processor_init_pdc(&data->acpi_data, cpu, &arg_list);
 	result = acpi_processor_register_performance(&data->acpi_data, cpu);
-	data->acpi_data.pdc = NULL;
 
 	if (result)
 		goto err_free;