Awesome

Original Description:

IOWMIFamily driver coded by hotKoffy over at InsanelyMac. http://www.insanelymac.com/forum/topic/248116-netbook-hot-key-driver-asus-dell-hp/

Last update: 18 sept 2011

I've wrote a driver for my Asus EEEPC 1201N since the existing one didn't worked after sleep. It is base on the WMI device you can find in the DSDT (PNP0C14 + ASUSWMI), so I think it can works with other asus product shipped with win7. Feel free to try and report.

Allowing the driver to work

To make sure this driver can attach you have to do some modification on WMI Device in your DSDT. Generally you would have something similar to:

	Device (AMW0)
	{
		Name (_HID, EisaId ("PNP0C14"))
		Name (_UID, Zero)
		Method (_STA, 0, NotSerialized)
		{
        	If (LEqual (MSOS (), MSW7)) //check if OS Windows 7
        	{
            	Return (0x0F) // means device is enabled   
            }
            	Return (Zero) //means device is disabled   
        }
        ...

We don't need to be checking for OS to be Windows 7 as in our case OS is Darwin. So you will need to remove this check if you have it in your DSDT, make _STA always Return (0x0F). Secondly, we need to be changing the _UID

• For ASUS put "ASUSMWI" instead of Zero (or 0x00 - depends on the decompiler you've used)
• For HP put "HPWMI"
• For Dell put "DELLWMI"

If there are several PNP0C14, locate the one with a Method (_WED..., if there are several, try all. Remove any other hotkey driver before trying it ! I.e. remove, rebuild kext cache and reboot.

Features

• Features on ASUS: keystrokes to system: SOUND_UP (0x30), SOUND_DOWN (0x31), MUTE (0x32), BRIGHTNESS_UP (0x11), BRIGHTNESS_DOWN (0x20), VIDMIRROR (0xCC) toggle between extended desktop and clone mode

  Hardware control: BRIGHTNESS ON/OFF (0xE9), BLUETOOTH ON/OFF (0x88), TRACKPAD ON/OFF (0x6B) only lights LED, disabling has to be coded in from PS2 driver, done by RehabMan.

• Features on Dell: keystrokes to system: SOUND_UP (0xe030), SOUND_DOWN (0xe02e), MUTE (0xe020), BRIGHTNESS_UP (0xe006), BRIGHTNESS_DOWN (0xe005), VIDMIRROR (0xe00b)

• Features on HP: keystrokes to system: BRIGHTNESS_UP (0x02), BRIGHTNESS_DOWN (0x03)

WMI on newer Dell machines

EC queries usually call for WMI notifications and send messages that need handling. Not all the keys on newer Dell machines utilize WMI, some are still tied to plain old PS/2 scancodes. For my particular laptop (Vostro 3450) only brightness keys are tied to WMI and do not generate regular scancodes when pressed. Here's an overview:

Decrease brighntess:

		Method (_Q80, 0, NotSerialized)
		{
        	....
        	
          	If (PWRS) //if AC charger is connected
            {
            	Store (Local0, BRGA) //store brightness level into register for AC brightness
            }
            Else //if running on batteries
            {
            	Store (Local0, BRGD) //store brightness level into register for DC brightness
            }
        	Store (0x03, ^^^^AMW0.INF0)
        	Store (0x00, ^^^^AMW0.INF1)
        	Store (0xE005, ^^^^AMW0.INF2) //0xE005 is a message to decrease brightness
        	Store (Local0, ^^^^AMW0.INF3) //to a desired brightness level
        	If (LEqual (DMFG, Zero))
        	{
            	Notify (AMW0, 0xD0) //notify to perform action
            }
      	} 
      	

Increase brighntess:

		Method (_Q81, 0, NotSerialized)
		{                                        
        	....
        	
        	If (PWRS)
            {
            	Store (Local0, BRGA)
            }
            Else
            {
            	Store (Local0, BRGD)
            }
        	Store (0x03, ^^^^AMW0.INF0)
        	Store (0x00, ^^^^AMW0.INF1)
        	Store (0xE006, ^^^^AMW0.INF2) //0xE006 is a message to increase brightness
        	Store (Local0, ^^^^AMW0.INF3) //to a desired brightness level
        	If (LEqual (DMFG, Zero))
        	{
            	Notify (AMW0, 0xD0) //notify to perform action
            }
        }
        

Now let's see how WMI reacts to these notifications from EC queries:

        Method (_WED, 1, NotSerialized)
        {
            If (LEqual (Arg0, 0xD0)) //every EC Query notifies AMW0 with this argument
            {
                Return (INFO) //so array INFO is being returned after each query
            }
            CLBY (INFO)
            Store (Arg0, INFO) //then argument (0xD0 as well) is stored in buffer, overweriting INF0
            Return (INFO)
        }

This means that first some value (in brightness control scenario it's 0x03) is being written into INF0 from within EC queries, then _WED returs it once, then returs 0xD0 again after INF0 is overwritten.

As this IOWMIFamily driver analyzes the output from _WED's first element (0 array element), in both cases it would get a value of 0x03 and 0xD0. Neither of those correspond to any predefined hotkey codes in plugins, so nothing happens.

        Name (INFO, Buffer (0x80) {})
        CreateWordField (INFO, 0x00, INF0)
        CreateWordField (INFO, 0x02, INF1)
        CreateWordField (INFO, 0x04, INF2)          
        CreateWordField (INFO, 0x06, INF3) 
        CreateWordField (INFO, 0x08, INF4)
        CreateWordField (INFO, 0x0A, INF5)
        CreateWordField (INFO, 0x0C, INF6)
        CreateWordField (INFO, 0x0E, INF7)
        

INF2 is the 4th and 5th byte of this INFO buffer returned by _WED, this one holds the code we are interested to parse by driver to be able to perform certain action.