--- f1fb411d9e4fa68948c2e5997759e3e47f69a06c
+++ ca6b33667f54c29d6f5f87126c632e9448d5bba2
@@ -518,8 +518,13 @@ static int __init init_sysfs(void)
 	int error;
 
 	error = sysdev_class_register(&oprofile_sysclass);
-	if (!error)
-		error = sysdev_register(&device_oprofile);
+	if (error)
+		return error;
+
+	error = sysdev_register(&device_oprofile);
+	if (error)
+		sysdev_class_unregister(&oprofile_sysclass);
+
 	return error;
 }
 
@@ -530,8 +535,10 @@ static void exit_sysfs(void)
 }
 
 #else
-#define init_sysfs() do { } while (0)
-#define exit_sysfs() do { } while (0)
+
+static inline int  init_sysfs(void) { return 0; }
+static inline void exit_sysfs(void) { }
+
 #endif /* CONFIG_PM */
 
 static int __init p4_init(char **cpu_type)
@@ -584,6 +591,18 @@ static int __init ppro_init(char **cpu_t
 	if (force_arch_perfmon && cpu_has_arch_perfmon)
 		return 0;
 
+	/*
+	 * Documentation on identifying Intel processors by CPU family
+	 * and model can be found in the Intel Software Developer's
+	 * Manuals (SDM):
+	 *
+	 *  http://www.intel.com/products/processor/manuals/
+	 *
+	 * As of May 2010 the documentation for this was in the:
+	 * "Intel 64 and IA-32 Architectures Software Developer's
+	 * Manual Volume 3B: System Programming Guide", "Table B-1
+	 * CPUID Signature Values of DisplayFamily_DisplayModel".
+	 */
 	switch (cpu_model) {
 	case 0 ... 2:
 		*cpu_type = "i386/ppro";
@@ -602,15 +621,19 @@ static int __init ppro_init(char **cpu_t
 	case 14:
 		*cpu_type = "i386/core";
 		break;
-	case 15: case 23:
+	case 0x0f:
+	case 0x16:
+	case 0x17:
+	case 0x1d:
 		*cpu_type = "i386/core_2";
 		break;
+	case 0x1a:
+	case 0x1e:
 	case 0x2e:
-	case 26:
 		spec = &op_arch_perfmon_spec;
 		*cpu_type = "i386/core_i7";
 		break;
-	case 28:
+	case 0x1c:
 		*cpu_type = "i386/atom";
 		break;
 	default:
@@ -632,6 +655,8 @@ int __init op_nmi_init(struct oprofile_o
 	char *cpu_type = NULL;
 	int ret = 0;
 
+	using_nmi = 0;
+
 	if (!cpu_has_apic)
 		return -ENODEV;
 
@@ -714,7 +739,10 @@ int __init op_nmi_init(struct oprofile_o
 
 	mux_init(ops);
 
-	init_sysfs();
+	ret = init_sysfs();
+	if (ret)
+		return ret;
+
 	using_nmi = 1;
 	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
 	return 0;