[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>

2 files changed, 0 insertions, 79 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index 871366b83b3f..31ce890865d5 100644
--- a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -297,68 +297,6 @@ acpi_cpufreq_guess_freq (
 }
 
 
-/* 
- * acpi_processor_cpu_init_pdc_est - 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, for Enhanced Speedstep. Actual call to _PDC is done in
- * driver/acpi/processor.c
- */
-static void 
-acpi_processor_cpu_init_pdc_est(
-                struct acpi_processor_performance *perf, 
-                unsigned int cpu,
-                struct acpi_object_list *obj_list
-                )
-{
-        union acpi_object *obj;
-        u32 *buf;
-        struct cpuinfo_x86 *c = cpu_data + cpu;
-        dprintk("acpi_processor_cpu_init_pdc_est\n");
-
-        if (!cpu_has(c, X86_FEATURE_EST))
-                return;
-
-        /* 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;
-}
- 
-
-/* CPU specific PDC initialization */
-static void 
-acpi_processor_cpu_init_pdc(
-                struct acpi_processor_performance *perf, 
-                unsigned int cpu,
-                struct acpi_object_list *obj_list
-                )
-{
-        struct cpuinfo_x86 *c = cpu_data + cpu;
-        dprintk("acpi_processor_cpu_init_pdc\n");
-        perf->pdc = NULL;
-        if (cpu_has(c, X86_FEATURE_EST))
-                acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);
-        return;
-}
-
-
 static int
 acpi_cpufreq_cpu_init (
         struct cpufreq_policy   *policy)
@@ -373,9 +311,6 @@ acpi_cpufreq_cpu_init (
         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 = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
         if (!data)
@@ -383,9 +318,7 @@ acpi_cpufreq_cpu_init (
 
         acpi_io_data[cpu] = data;
 
-        acpi_processor_cpu_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;
diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
index edb9873e27e3..d93023438c4f 100644
--- a/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
+++ b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
@@ -364,22 +364,10 @@ static struct acpi_processor_performance p;
  */
 static int centrino_cpu_init_acpi(struct cpufreq_policy *policy)
 {
-        union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
-        u32                             arg0_buf[3];
-        struct acpi_object_list         arg_list = {1, &arg0};
         unsigned long                   cur_freq;
         int                             result = 0, i;
         unsigned int                    cpu = policy->cpu;
 
-        /* _PDC settings */
-        arg0.buffer.length = 12;
-        arg0.buffer.pointer = (u8 *) arg0_buf;
-        arg0_buf[0] = ACPI_PDC_REVISION_ID;
-        arg0_buf[1] = 1;
-        arg0_buf[2] = ACPI_PDC_EST_CAPABILITY_SMP_MSR;
-
-        p.pdc = &arg_list;
-
         /* register with ACPI core */
         if (acpi_processor_register_performance(&p, cpu)) {
                 dprintk(KERN_INFO PFX "obtaining ACPI data failed\n");