diff -uNr -X linux-2.6.15/Documentation/dontdiff linux-2.6.15/drivers/acpi/ac.c linux-2.6.15.4/drivers/acpi/ac.c
--- linux-2.6.15/drivers/acpi/ac.c	2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6.15.4/drivers/acpi/ac.c	2006-02-19 17:50:20.000000000 +0100
@@ -29,6 +29,7 @@
 #include <linux/types.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/cpufreq.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 
@@ -213,6 +214,8 @@
 		break;
 	}
 
+	cpufreq_reinit();
+
 	return_VOID;
 }
 
diff -uNr -X linux-2.6.15/Documentation/dontdiff linux-2.6.15/drivers/cpufreq/cpufreq.c linux-2.6.15.4/drivers/cpufreq/cpufreq.c
--- linux-2.6.15/drivers/cpufreq/cpufreq.c	2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6.15.4/drivers/cpufreq/cpufreq.c	2006-02-21 20:00:06.000000000 +0100
@@ -863,6 +863,30 @@
 
 
 /**
+ * cpufreq_reinit - reinitialize CPU frequency of all CPUs
+ */
+
+int cpufreq_reinit(void)
+{
+	int cpu, ret;
+	struct cpufreq_policy *policy;
+
+	for_each_online_cpu (cpu) {
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy)
+			return -EINVAL;
+		ret = cpufreq_driver->exit(policy);
+		if (ret)
+			return ret;
+		ret = cpufreq_driver->init(policy);
+		if (ret)
+			return ret;
+	}
+	return (0);
+}
+EXPORT_SYMBOL(cpufreq_reinit);
+
+/**
  *	cpufreq_suspend - let the low level driver prepare for suspend
  */
 
--- linux-2.6.15/include/linux/cpufreq.h	2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6.15.4/include/linux/cpufreq.h	2006-02-21 20:37:27.000000000 +0100
@@ -256,6 +256,11 @@
 /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
 unsigned int cpufreq_get(unsigned int cpu);
 
+#ifdef CONFIG_CPU_FREQ
+int cpu_freq_reinit(void);
+#else
+static inline int cpu_freq_reinit(void) { return 0; }
+#endif
 
 /*********************************************************************
  *                       CPUFREQ DEFAULT GOVERNOR                    *