* Committed Clemens Zeidler's Intel speedstep driver. Thanks a lot, Clemens!

This is a very welcome addition.
* There are a few issues, and maybe questionable decisions (like the dependence
  on ACPI), but I see no reason why it shouldn't be added in its current form
  already.
* Unfortunately, I could not test it yet, though, as the CPU of my laptop is
  not supported; will see if I can find a supported hardware, though.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28903 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/device/power_managment.h

@@ -0,0 +1,39 @@
+#ifndef POWER_MANAGMENT_H
+#define POWER_MANAGMENT_H
+
+#include <Drivers.h>
+
+// io controls
+enum { 
+	// ioctl response with kMagicFreqID
+	IDENTIFY_DEVICE = B_DEVICE_OP_CODES_END + 20001,
+	
+	// CPU Frequence:
+	// get a list of freq_info, the list is terminated with a element with
+	// frequency = 0
+	GET_CPU_FREQ_STATES = B_DEVICE_OP_CODES_END + 20005,
+	// get and set a freq_info
+	GET_CURENT_CPU_FREQ_STATE,
+	SET_CPU_FREQ_STATE,
+	// start watching for frequency changes, ioctl blocks until the frequency
+	// has changed
+	WATCH_CPU_FREQ,
+	// stop all watching ioctl, ioctl return B_ERROR
+	STOP_WATCHING_CPU_FREQ
+}; 
+
+// CPU Frequence:
+// magic id returned by IDENTIFY_DEVICE
+const uint32 kMagicFreqID = 48921;
+
+#define MAX_CPU_FREQUENCY_STATES 10
+
+typedef struct {
+	uint16			frequency;	// [Mhz]
+	uint16			volts;
+	uint16			id;
+	int				power;
+} freq_info;
+
+
+#endif