ACPI: processor: call _PDC early

We discovered that at least one machine (HP Envy), methods in the DSDT
attempt to call external methods defined in a dynamically loaded SSDT.

Unfortunately, the DSDT methods we are trying to call are part of the
EC initialization, which happens very early, and the the dynamic SSDT
is only loaded when a processor _PDC method runs much later.

This results in namespace lookup errors for the (as of yet) undefined
methods.

Since Windows doesn't have any issues with this machine, we take it
as a hint that they must be evaluating _PDC much earlier than we are.

Thus, the proper thing for Linux to do should be to match the Windows
implementation more closely.

Provide a mechanism to call _PDC before we enable the EC. Doing so loads
the dynamic tables, and allows the EC to be enabled correctly.

The ACPI processor driver will still evaluate _PDC in its .add() method
to cover the hotplug case.

Resolves: http://bugzilla.kernel.org/show_bug.cgi?id=14824

Cc: ming.m.lin@intel.com
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Makefile

@@ -32,6 +32,7 @@ acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
 #
 acpi-y				+= bus.o glue.o
 acpi-y				+= scan.o
+acpi-y				+= processor_pdc.o
 acpi-y				+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-y				+= pci_root.o pci_link.o pci_irq.o pci_bind.o

drivers/acpi/bus.c

@@ -888,6 +888,8 @@ static int __init acpi_bus_init(void)
 		goto error1;
 	}
 
+	acpi_early_processor_set_pdc();
+
 	/*
 	 * Maybe EC region is required at bus_scan/acpi_get_devices. So it
 	 * is necessary to enable it as early as possible.

drivers/acpi/internal.h

@@ -43,6 +43,7 @@ int acpi_power_transition(struct acpi_device *device, int state);
 extern int acpi_power_nocheck;
 
 int acpi_wakeup_device_init(void);
+void acpi_early_processor_set_pdc(void);
 
 /* --------------------------------------------------------------------------
                                   Embedded Controller

drivers/acpi/processor_core.c

@@ -124,29 +124,6 @@ static const struct file_operations acpi_processor_info_fops = {
 
 DEFINE_PER_CPU(struct acpi_processor *, processors);
 struct acpi_processor_errata errata __read_mostly;
-static int set_no_mwait(const struct dmi_system_id *id)
-{
-	printk(KERN_NOTICE PREFIX "%s detected - "
-		"disabling mwait for CPU C-states\n", id->ident);
-	idle_nomwait = 1;
-	return 0;
-}
-
-static struct dmi_system_id __cpuinitdata processor_idle_dmi_table[] = {
-	{
-	set_no_mwait, "IFL91 board", {
-	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
-	DMI_MATCH(DMI_SYS_VENDOR, "ZEPTO"),
-	DMI_MATCH(DMI_PRODUCT_VERSION, "3215W"),
-	DMI_MATCH(DMI_BOARD_NAME, "IFL91") }, NULL},
-	{
-	set_no_mwait, "Extensa 5220", {
-	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
-	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
-	DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
-	DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
-	{},
-};
 
 /* --------------------------------------------------------------------------
                                 Errata Handling
@@ -276,45 +253,6 @@ static int acpi_processor_errata(struct acpi_processor *pr)
 	return result;
 }
 
-/* --------------------------------------------------------------------------
-                              Common ACPI processor functions
-   -------------------------------------------------------------------------- */
-
-/*
- * _PDC is required for a BIOS-OS handshake for most of the newer
- * ACPI processor features.
- */
-static int acpi_processor_set_pdc(struct acpi_processor *pr)
-{
-	struct acpi_object_list *pdc_in = pr->pdc;
-	acpi_status status = AE_OK;
-
-
-	if (!pdc_in)
-		return status;
-	if (idle_nomwait) {
-		/*
-		 * If mwait is disabled for CPU C-states, the C2C3_FFH access
-		 * mode will be disabled in the parameter of _PDC object.
-		 * Of course C1_FFH access mode will also be disabled.
-		 */
-		union acpi_object *obj;
-		u32 *buffer = NULL;
-
-		obj = pdc_in->pointer;
-		buffer = (u32 *)(obj->buffer.pointer);
-		buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
-
-	}
-	status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
-
-	if (ACPI_FAILURE(status))
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-		    "Could not evaluate _PDC, using legacy perf. control...\n"));
-
-	return status;
-}
-
 /* --------------------------------------------------------------------------
                               FS Interface (/proc)
    -------------------------------------------------------------------------- */
@@ -825,9 +763,7 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
 	}
 
 	/* _PDC call should be done before doing anything else (if reqd.). */
-	arch_acpi_processor_init_pdc(pr);
 	acpi_processor_set_pdc(pr);
-	arch_acpi_processor_cleanup_pdc(pr);
 
 #ifdef CONFIG_CPU_FREQ
 	acpi_processor_ppc_has_changed(pr, 0);
@@ -1145,11 +1081,6 @@ static int __init acpi_processor_init(void)
 	if (!acpi_processor_dir)
 		return -ENOMEM;
 #endif
-	/*
-	 * Check whether the system is DMI table. If yes, OSPM
-	 * should not use mwait for CPU-states.
-	 */
-	dmi_check_system(processor_idle_dmi_table);
 	result = cpuidle_register_driver(&acpi_idle_driver);
 	if (result < 0)
 		goto out_proc;

drivers/acpi/processor_pdc.c

+#include <linux/dmi.h>
+
+#include <acpi/acpi_drivers.h>
+#include <acpi/processor.h>
+
+#include "internal.h"
+
+#define PREFIX			"ACPI: "
+#define _COMPONENT		ACPI_PROCESSOR_COMPONENT
+ACPI_MODULE_NAME("processor_pdc");
+
+static int set_no_mwait(const struct dmi_system_id *id)
+{
+	printk(KERN_NOTICE PREFIX "%s detected - "
+		"disabling mwait for CPU C-states\n", id->ident);
+	idle_nomwait = 1;
+	return 0;
+}
+
+static struct dmi_system_id __cpuinitdata processor_idle_dmi_table[] = {
+	{
+	set_no_mwait, "IFL91 board", {
+	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
+	DMI_MATCH(DMI_SYS_VENDOR, "ZEPTO"),
+	DMI_MATCH(DMI_PRODUCT_VERSION, "3215W"),
+	DMI_MATCH(DMI_BOARD_NAME, "IFL91") }, NULL},
+	{
+	set_no_mwait, "Extensa 5220", {
+	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
+	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+	DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
+	DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
+	{},
+};
+
+/*
+ * _PDC is required for a BIOS-OS handshake for most of the newer
+ * ACPI processor features.
+ */
+static int acpi_processor_eval_pdc(struct acpi_processor *pr)
+{
+	struct acpi_object_list *pdc_in = pr->pdc;
+	acpi_status status = AE_OK;
+
+	if (!pdc_in)
+		return status;
+	if (idle_nomwait) {
+		/*
+		 * If mwait is disabled for CPU C-states, the C2C3_FFH access
+		 * mode will be disabled in the parameter of _PDC object.
+		 * Of course C1_FFH access mode will also be disabled.
+		 */
+		union acpi_object *obj;
+		u32 *buffer = NULL;
+
+		obj = pdc_in->pointer;
+		buffer = (u32 *)(obj->buffer.pointer);
+		buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
+
+	}
+	status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
+
+	if (ACPI_FAILURE(status))
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+		    "Could not evaluate _PDC, using legacy perf. control.\n"));
+
+	return status;
+}
+
+void acpi_processor_set_pdc(struct acpi_processor *pr)
+{
+	arch_acpi_processor_init_pdc(pr);
+	acpi_processor_eval_pdc(pr);
+	arch_acpi_processor_cleanup_pdc(pr);
+}
+EXPORT_SYMBOL_GPL(acpi_processor_set_pdc);
+
+static acpi_status
+early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	struct acpi_processor pr;
+
+	pr.handle = handle;
+
+	/* x86 implementation looks at pr.id to determine some
+	 * CPU capabilites. We can just hard code to 0 since we're
+	 * assuming the CPUs in the system are homogenous and all
+	 * have the same capabilities.
+	 */
+	pr.id = 0;
+
+	acpi_processor_set_pdc(&pr);
+
+	return AE_OK;
+}
+
+void acpi_early_processor_set_pdc(void)
+{
+	/*
+	 * Check whether the system is DMI table. If yes, OSPM
+	 * should not use mwait for CPU-states.
+	 */
+	dmi_check_system(processor_idle_dmi_table);
+
+	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
+			    ACPI_UINT32_MAX,
+			    early_init_pdc, NULL, NULL, NULL);
+}

include/acpi/processor.h

@@ -325,6 +325,9 @@ static inline int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
 
 #endif				/* CONFIG_CPU_FREQ */
 
+/* in processor_pdc.c */
+void acpi_processor_set_pdc(struct acpi_processor *pr);
+
 /* in processor_throttling.c */
 int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
 int acpi_processor_get_throttling_info(struct acpi_processor *pr);