[ACPI] add module parameters: processor.c2=[0,1] processor.c3=[0,1]

to disable/enable C2 or C3
blacklist entries for R40e and Medion 41700
http://bugme.osdl.org/show_bug.cgi?id=3549

from Andi Kleen

Documentation/kernel-parameters.txt

@@ -903,6 +903,11 @@ running once the system is up.
 	profile=	[KNL] Enable kernel profiling via /proc/profile
 			(param: profile step/bucket size as a power of 2)
 
+	processor.c2=	[HW, ACPI]
+	processor.c3=	[HW, ACPI]
+			0 - disable C2 or C3 idle power saving state.
+			1 - enable C2 or C3 (default unless DMI blacklist entry)
+
 	prompt_ramdisk=	[RAM] List of RAM disks to prompt for floppy disk
 			before loading.
 			See Documentation/ramdisk.txt.

drivers/acpi/processor.c

@@ -39,6 +39,8 @@
 #include <linux/cpufreq.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/dmi.h>
+#include <linux/moduleparam.h>
 
 #include <asm/io.h>
 #include <asm/system.h>
@@ -99,6 +101,8 @@ static struct acpi_driver acpi_processor_driver = {
 			},
 };
 
+static int c2 = -1;
+static int c3 = -1;
 
 struct acpi_processor_errata {
 	u8			smp;
@@ -140,6 +144,8 @@ static struct file_operations acpi_processor_limit_fops = {
 
 static struct acpi_processor	*processors[NR_CPUS];
 static struct acpi_processor_errata errata;
+module_param_named(c2, c2, bool, 0);
+module_param_named(c3, c3, bool, 0);
 static void (*pm_idle_save)(void);
 
 
@@ -651,6 +657,11 @@ acpi_processor_get_power_info (
 		else if (errata.smp)
 			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				"C2 not supported in SMP mode\n"));
+
+
+		else if (!c2) 
+			printk(KERN_INFO "C2 disabled\n");
+
 		/*
 		 * Otherwise we've met all of our C2 requirements.
 		 * Normalize the C2 latency to expidite policy.
@@ -706,6 +717,9 @@ acpi_processor_get_power_info (
 			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				"C3 not supported on PIIX4 with Type-F DMA\n"));
 		}
+		else if (!c3)
+			printk(KERN_INFO "C3 disabled\n");
+
 		/*
 		 * Otherwise we've met all of our C3 requirements.  
 		 * Normalize the C2 latency to expidite policy.  Enable
@@ -2438,6 +2452,29 @@ acpi_processor_remove (
 	return_VALUE(0);
 }
 
+/* IBM ThinkPad R40e crashes mysteriously when going into C2 or C3. 
+   For now disable this. Probably a bug somewhere else. */
+static int no_c2c3(struct dmi_system_id *id)
+{
+	printk(KERN_INFO 
+	       "%s detected - C2,C3 disabled. Overwrite with \"processor.c2=1 processor.c3=1\n\"",
+	       id->ident);
+	if (c2 == -1) 
+		c2 = 0;
+	if (c3 == -1) 
+		c3 = 0; 
+	return 0;
+}
+
+static struct dmi_system_id __initdata processor_dmi_table[] = { 
+	{ no_c2c3, "IBM ThinkPad R40e", {
+	  DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
+	  DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }},
+	{ no_c2c3, "Medion 41700", {
+	  DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
+	  DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J") }},
+	{},
+};
 
 static int __init
 acpi_processor_init (void)
@@ -2464,6 +2501,8 @@ acpi_processor_init (void)
 
 	acpi_processor_ppc_init();
 
+	dmi_check_system(processor_dmi_table); 
+
 	return_VALUE(0);
 }