summaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
diff options
context:
space:
mode:
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 /arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
parentd2149b542382bfc206cb28485108f6470c979566 (diff)
downloadop-kernel-dev-05131ecc99ea9da7f45ba3058fe8a2c1d0ceeab8.zip
op-kernel-dev-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 'arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c')
-rw-r--r--arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c67
1 files changed, 0 insertions, 67 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index 871366b..31ce890 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;
OpenPOWER on IntegriCloud