| 		     ThinkPad ACPI Extras Driver | 
 |  | 
 |                             Version 0.16 | 
 |                           August 2nd, 2007 | 
 |  | 
 |                Borislav Deianov <borislav@users.sf.net> | 
 |              Henrique de Moraes Holschuh <hmh@hmh.eng.br> | 
 |                       http://ibm-acpi.sf.net/ | 
 |  | 
 |  | 
 | This is a Linux driver for the IBM and Lenovo ThinkPad laptops. It | 
 | supports various features of these laptops which are accessible | 
 | through the ACPI and ACPI EC framework, but not otherwise fully | 
 | supported by the generic Linux ACPI drivers. | 
 |  | 
 | This driver used to be named ibm-acpi until kernel 2.6.21 and release | 
 | 0.13-20070314.  It used to be in the drivers/acpi tree, but it was | 
 | moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel | 
 | 2.6.22, and release 0.14. | 
 |  | 
 |  | 
 | Status | 
 | ------ | 
 |  | 
 | The features currently supported are the following (see below for | 
 | detailed description): | 
 |  | 
 | 	- Fn key combinations | 
 | 	- Bluetooth enable and disable | 
 | 	- video output switching, expansion control | 
 | 	- ThinkLight on and off | 
 | 	- limited docking and undocking | 
 | 	- UltraBay eject | 
 | 	- CMOS control | 
 | 	- LED control | 
 | 	- ACPI sounds | 
 | 	- temperature sensors | 
 | 	- Experimental: embedded controller register dump | 
 | 	- LCD brightness control | 
 | 	- Volume control | 
 | 	- Fan control and monitoring: fan speed, fan enable/disable | 
 | 	- Experimental: WAN enable and disable | 
 |  | 
 | A compatibility table by model and feature is maintained on the web | 
 | site, http://ibm-acpi.sf.net/. I appreciate any success or failure | 
 | reports, especially if they add to or correct the compatibility table. | 
 | Please include the following information in your report: | 
 |  | 
 | 	- ThinkPad model name | 
 | 	- a copy of your DSDT, from /proc/acpi/dsdt | 
 | 	- a copy of the output of dmidecode, with serial numbers | 
 | 	  and UUIDs masked off | 
 | 	- which driver features work and which don't | 
 | 	- the observed behavior of non-working features | 
 |  | 
 | Any other comments or patches are also more than welcome. | 
 |  | 
 |  | 
 | Installation | 
 | ------------ | 
 |  | 
 | If you are compiling this driver as included in the Linux kernel | 
 | sources, simply enable the CONFIG_THINKPAD_ACPI option, and optionally | 
 | enable the CONFIG_THINKPAD_ACPI_BAY option if you want the | 
 | thinkpad-specific bay functionality. | 
 |  | 
 | Features | 
 | -------- | 
 |  | 
 | The driver exports two different interfaces to userspace, which can be | 
 | used to access the features it provides.  One is a legacy procfs-based | 
 | interface, which will be removed at some time in the distant future. | 
 | The other is a new sysfs-based interface which is not complete yet. | 
 |  | 
 | The procfs interface creates the /proc/acpi/ibm directory.  There is a | 
 | file under that directory for each feature it supports.  The procfs | 
 | interface is mostly frozen, and will change very little if at all: it | 
 | will not be extended to add any new functionality in the driver, instead | 
 | all new functionality will be implemented on the sysfs interface. | 
 |  | 
 | The sysfs interface tries to blend in the generic Linux sysfs subsystems | 
 | and classes as much as possible.  Since some of these subsystems are not | 
 | yet ready or stabilized, it is expected that this interface will change, | 
 | and any and all userspace programs must deal with it. | 
 |  | 
 |  | 
 | Notes about the sysfs interface: | 
 |  | 
 | Unlike what was done with the procfs interface, correctness when talking | 
 | to the sysfs interfaces will be enforced, as will correctness in the | 
 | thinkpad-acpi's implementation of sysfs interfaces. | 
 |  | 
 | Also, any bugs in the thinkpad-acpi sysfs driver code or in the | 
 | thinkpad-acpi's implementation of the sysfs interfaces will be fixed for | 
 | maximum correctness, even if that means changing an interface in | 
 | non-compatible ways.  As these interfaces mature both in the kernel and | 
 | in thinkpad-acpi, such changes should become quite rare. | 
 |  | 
 | Applications interfacing to the thinkpad-acpi sysfs interfaces must | 
 | follow all sysfs guidelines and correctly process all errors (the sysfs | 
 | interface makes extensive use of errors).  File descriptors and open / | 
 | close operations to the sysfs inodes must also be properly implemented. | 
 |  | 
 | The version of thinkpad-acpi's sysfs interface is exported by the driver | 
 | as a driver attribute (see below). | 
 |  | 
 | Sysfs driver attributes are on the driver's sysfs attribute space, | 
 | for 2.6.23 this is /sys/bus/platform/drivers/thinkpad_acpi/ and | 
 | /sys/bus/platform/drivers/thinkpad_hwmon/ | 
 |  | 
 | Sysfs device attributes are on the thinkpad_acpi device sysfs attribute | 
 | space, for 2.6.23 this is /sys/devices/platform/thinkpad_acpi/. | 
 |  | 
 | Sysfs device attributes for the sensors and fan are on the | 
 | thinkpad_hwmon device's sysfs attribute space, but you should locate it | 
 | looking for a hwmon device with the name attribute of "thinkpad". | 
 |  | 
 | Driver version | 
 | -------------- | 
 |  | 
 | procfs: /proc/acpi/ibm/driver | 
 | sysfs driver attribute: version | 
 |  | 
 | The driver name and version. No commands can be written to this file. | 
 |  | 
 | Sysfs interface version | 
 | ----------------------- | 
 |  | 
 | sysfs driver attribute: interface_version | 
 |  | 
 | Version of the thinkpad-acpi sysfs interface, as an unsigned long | 
 | (output in hex format: 0xAAAABBCC), where: | 
 | 	AAAA - major revision | 
 | 	BB - minor revision | 
 | 	CC - bugfix revision | 
 |  | 
 | The sysfs interface version changelog for the driver can be found at the | 
 | end of this document.  Changes to the sysfs interface done by the kernel | 
 | subsystems are not documented here, nor are they tracked by this | 
 | attribute. | 
 |  | 
 | Changes to the thinkpad-acpi sysfs interface are only considered | 
 | non-experimental when they are submitted to Linux mainline, at which | 
 | point the changes in this interface are documented and interface_version | 
 | may be updated.  If you are using any thinkpad-acpi features not yet | 
 | sent to mainline for merging, you do so on your own risk: these features | 
 | may disappear, or be implemented in a different and incompatible way by | 
 | the time they are merged in Linux mainline. | 
 |  | 
 | Changes that are backwards-compatible by nature (e.g. the addition of | 
 | attributes that do not change the way the other attributes work) do not | 
 | always warrant an update of interface_version.  Therefore, one must | 
 | expect that an attribute might not be there, and deal with it properly | 
 | (an attribute not being there *is* a valid way to make it clear that a | 
 | feature is not available in sysfs). | 
 |  | 
 | Hot keys | 
 | -------- | 
 |  | 
 | procfs: /proc/acpi/ibm/hotkey | 
 | sysfs device attribute: hotkey_* | 
 |  | 
 | In a ThinkPad, the ACPI HKEY handler is responsible for comunicating | 
 | some important events and also keyboard hot key presses to the operating | 
 | system.  Enabling the hotkey functionality of thinkpad-acpi signals the | 
 | firmware that such a driver is present, and modifies how the ThinkPad | 
 | firmware will behave in many situations. | 
 |  | 
 | The driver enables the hot key feature automatically when loaded.  The | 
 | feature can later be disabled and enabled back at runtime.  The driver | 
 | will also restore the hot key feature to its previous state and mask | 
 | when it is unloaded. | 
 |  | 
 | When the hotkey feature is enabled and the hot key mask is set (see | 
 | below), the driver will report HKEY events in the following format: | 
 |  | 
 | 	ibm/hotkey HKEY 00000080 0000xxxx | 
 |  | 
 | Some of these events refer to hot key presses, but not all. | 
 |  | 
 | The driver will generate events over the input layer for hot keys and | 
 | radio switches, and over the ACPI netlink layer for other events.  The | 
 | input layer support accepts the standard IOCTLs to remap the keycodes | 
 | assigned to each hot key. | 
 |  | 
 | The hot key bit mask allows some control over which hot keys generate | 
 | events.  If a key is "masked" (bit set to 0 in the mask), the firmware | 
 | will handle it.  If it is "unmasked", it signals the firmware that | 
 | thinkpad-acpi would prefer to handle it, if the firmware would be so | 
 | kind to allow it (and it often doesn't!). | 
 |  | 
 | Not all bits in the mask can be modified.  Not all bits that can be | 
 | modified do anything.  Not all hot keys can be individually controlled | 
 | by the mask.  Some models do not support the mask at all, and in those | 
 | models, hot keys cannot be controlled individually.  The behaviour of | 
 | the mask is, therefore, higly dependent on the ThinkPad model. | 
 |  | 
 | Note that unmasking some keys prevents their default behavior.  For | 
 | example, if Fn+F5 is unmasked, that key will no longer enable/disable | 
 | Bluetooth by itself. | 
 |  | 
 | Note also that not all Fn key combinations are supported through ACPI. | 
 | For example, on the X40, the brightness, volume and "Access IBM" buttons | 
 | do not generate ACPI events even with this driver.  They *can* be used | 
 | through the "ThinkPad Buttons" utility, see http://www.nongnu.org/tpb/ | 
 |  | 
 | procfs notes: | 
 |  | 
 | The following commands can be written to the /proc/acpi/ibm/hotkey file: | 
 |  | 
 | 	echo enable > /proc/acpi/ibm/hotkey -- enable the hot keys feature | 
 | 	echo disable > /proc/acpi/ibm/hotkey -- disable the hot keys feature | 
 | 	echo 0xffffffff > /proc/acpi/ibm/hotkey -- enable all hot keys | 
 | 	echo 0 > /proc/acpi/ibm/hotkey -- disable all possible hot keys | 
 | 	... any other 8-hex-digit mask ... | 
 | 	echo reset > /proc/acpi/ibm/hotkey -- restore the original mask | 
 |  | 
 | sysfs notes: | 
 |  | 
 | 	hotkey_bios_enabled: | 
 | 		Returns the status of the hot keys feature when | 
 | 		thinkpad-acpi was loaded.  Upon module unload, the hot | 
 | 		key feature status will be restored to this value. | 
 |  | 
 | 		0: hot keys were disabled | 
 | 		1: hot keys were enabled (unusual) | 
 |  | 
 | 	hotkey_bios_mask: | 
 | 		Returns the hot keys mask when thinkpad-acpi was loaded. | 
 | 		Upon module unload, the hot keys mask will be restored | 
 | 		to this value. | 
 |  | 
 | 	hotkey_enable: | 
 | 		Enables/disables the hot keys feature, and reports | 
 | 		current status of the hot keys feature. | 
 |  | 
 | 		0: disables the hot keys feature / feature disabled | 
 | 		1: enables the hot keys feature / feature enabled | 
 |  | 
 | 	hotkey_mask: | 
 | 		bit mask to enable driver-handling and ACPI event | 
 | 		generation for each hot key (see above).  Returns the | 
 | 		current status of the hot keys mask, and allows one to | 
 | 		modify it. | 
 |  | 
 | 	hotkey_all_mask: | 
 | 		bit mask that should enable event reporting for all | 
 | 		supported hot keys, when echoed to hotkey_mask above. | 
 | 		Unless you know which events need to be handled | 
 | 		passively (because the firmware *will* handle them | 
 | 		anyway), do *not* use hotkey_all_mask.  Use | 
 | 		hotkey_recommended_mask, instead. You have been warned. | 
 |  | 
 | 	hotkey_recommended_mask: | 
 | 		bit mask that should enable event reporting for all | 
 | 		supported hot keys, except those which are always | 
 | 		handled by the firmware anyway.  Echo it to | 
 | 		hotkey_mask above, to use. | 
 |  | 
 | 	hotkey_radio_sw: | 
 | 		if the ThinkPad has a hardware radio switch, this | 
 | 		attribute will read 0 if the switch is in the "radios | 
 | 		disabled" postition, and 1 if the switch is in the | 
 | 		"radios enabled" position. | 
 |  | 
 | 	hotkey_report_mode: | 
 | 		Returns the state of the procfs ACPI event report mode | 
 | 		filter for hot keys.  If it is set to 1 (the default), | 
 | 		all hot key presses are reported both through the input | 
 | 		layer and also as ACPI events through procfs (but not | 
 | 		through netlink).  If it is set to 2, hot key presses | 
 | 		are reported only through the input layer. | 
 |  | 
 | 		This attribute is read-only in kernels 2.6.23 or later, | 
 | 		and read-write on earlier kernels. | 
 |  | 
 | 		May return -EPERM (write access locked out by module | 
 | 		parameter) or -EACCES (read-only). | 
 |  | 
 | input layer notes: | 
 |  | 
 | A Hot key is mapped to a single input layer EV_KEY event, possibly | 
 | followed by an EV_MSC MSC_SCAN event that shall contain that key's scan | 
 | code.  An EV_SYN event will always be generated to mark the end of the | 
 | event block. | 
 |  | 
 | Do not use the EV_MSC MSC_SCAN events to process keys.  They are to be | 
 | used as a helper to remap keys, only.  They are particularly useful when | 
 | remapping KEY_UNKNOWN keys. | 
 |  | 
 | The events are available in an input device, with the following id: | 
 |  | 
 | 	Bus:		BUS_HOST | 
 | 	vendor:		0x1014 (PCI_VENDOR_ID_IBM)  or | 
 | 			0x17aa (PCI_VENDOR_ID_LENOVO) | 
 | 	product:	0x5054 ("TP") | 
 | 	version:	0x4101 | 
 |  | 
 | The version will have its LSB incremented if the keymap changes in a | 
 | backwards-compatible way.  The MSB shall always be 0x41 for this input | 
 | device.  If the MSB is not 0x41, do not use the device as described in | 
 | this section, as it is either something else (e.g. another input device | 
 | exported by a thinkpad driver, such as HDAPS) or its functionality has | 
 | been changed in a non-backwards compatible way. | 
 |  | 
 | Adding other event types for other functionalities shall be considered a | 
 | backwards-compatible change for this input device. | 
 |  | 
 | Thinkpad-acpi Hot Key event map (version 0x4101): | 
 |  | 
 | ACPI	Scan | 
 | event	code	Key		Notes | 
 |  | 
 | 0x1001	0x00	FN+F1		- | 
 | 0x1002	0x01	FN+F2		IBM: battery (rare) | 
 | 				Lenovo: Screen lock | 
 |  | 
 | 0x1003	0x02	FN+F3		Many IBM models always report | 
 | 				this hot key, even with hot keys | 
 | 				disabled or with Fn+F3 masked | 
 | 				off | 
 | 				IBM: screen lock | 
 | 				Lenovo: battery | 
 |  | 
 | 0x1004	0x03	FN+F4		Sleep button (ACPI sleep button | 
 | 				semanthics, i.e. sleep-to-RAM). | 
 | 				It is always generate some kind | 
 | 				of event, either the hot key | 
 | 				event or a ACPI sleep button | 
 | 				event. The firmware may | 
 | 				refuse to generate further FN+F4 | 
 | 				key presses until a S3 or S4 ACPI | 
 | 				sleep cycle is performed or some | 
 | 				time passes. | 
 |  | 
 | 0x1005	0x04	FN+F5		Radio.  Enables/disables | 
 | 				the internal BlueTooth hardware | 
 | 				and W-WAN card if left in control | 
 | 				of the firmware.  Does not affect | 
 | 				the WLAN card. | 
 | 				Should be used to turn on/off all | 
 | 				radios (bluetooth+W-WAN+WLAN), | 
 | 				really. | 
 |  | 
 | 0x1006	0x05	FN+F6		- | 
 |  | 
 | 0x1007	0x06	FN+F7		Video output cycle. | 
 | 				Do you feel lucky today? | 
 |  | 
 | 0x1008	0x07	FN+F8		IBM: toggle screen expand | 
 | 				Lenovo: configure ultranav | 
 |  | 
 | 0x1009	0x08	FN+F9		- | 
 | 	..	..		.. | 
 | 0x100B	0x0A	FN+F11		- | 
 |  | 
 | 0x100C	0x0B	FN+F12		Sleep to disk.  You are always | 
 | 				supposed to handle it yourself, | 
 | 				either through the ACPI event, | 
 | 				or through a hotkey event. | 
 | 				The firmware may refuse to | 
 | 				generate further FN+F4 key | 
 | 				press events until a S3 or S4 | 
 | 				ACPI sleep cycle is performed, | 
 | 				or some time passes. | 
 |  | 
 | 0x100D	0x0C	FN+BACKSPACE	- | 
 | 0x100E	0x0D	FN+INSERT	- | 
 | 0x100F	0x0E	FN+DELETE	- | 
 |  | 
 | 0x1010	0x0F	FN+HOME		Brightness up.  This key is | 
 | 				always handled by the firmware | 
 | 				in IBM ThinkPads, even when | 
 | 				unmasked.  Just leave it alone. | 
 | 				For Lenovo ThinkPads with a new | 
 | 				BIOS, it has to be handled either | 
 | 				by the ACPI OSI, or by userspace. | 
 | 0x1011	0x10	FN+END		Brightness down.  See brightness | 
 | 				up for details. | 
 |  | 
 | 0x1012	0x11	FN+PGUP		Thinklight toggle.  This key is | 
 | 				always handled by the firmware, | 
 | 				even when unmasked. | 
 |  | 
 | 0x1013	0x12	FN+PGDOWN	- | 
 |  | 
 | 0x1014	0x13	FN+SPACE	Zoom key | 
 |  | 
 | 0x1015	0x14	VOLUME UP	Internal mixer volume up. This | 
 | 				key is always handled by the | 
 | 				firmware, even when unmasked. | 
 | 				NOTE: Lenovo seems to be changing | 
 | 				this. | 
 | 0x1016	0x15	VOLUME DOWN	Internal mixer volume up. This | 
 | 				key is always handled by the | 
 | 				firmware, even when unmasked. | 
 | 				NOTE: Lenovo seems to be changing | 
 | 				this. | 
 | 0x1017	0x16	MUTE		Mute internal mixer. This | 
 | 				key is always handled by the | 
 | 				firmware, even when unmasked. | 
 |  | 
 | 0x1018	0x17	THINKPAD	Thinkpad/Access IBM/Lenovo key | 
 |  | 
 | 0x1019	0x18	unknown | 
 | ..	..	.. | 
 | 0x1020	0x1F	unknown | 
 |  | 
 | The ThinkPad firmware does not allow one to differentiate when most hot | 
 | keys are pressed or released (either that, or we don't know how to, yet). | 
 | For these keys, the driver generates a set of events for a key press and | 
 | immediately issues the same set of events for a key release.  It is | 
 | unknown by the driver if the ThinkPad firmware triggered these events on | 
 | hot key press or release, but the firmware will do it for either one, not | 
 | both. | 
 |  | 
 | If a key is mapped to KEY_RESERVED, it generates no input events at all. | 
 | If a key is mapped to KEY_UNKNOWN, it generates an input event that | 
 | includes an scan code.  If a key is mapped to anything else, it will | 
 | generate input device EV_KEY events. | 
 |  | 
 | Non hot-key ACPI HKEY event map: | 
 | 0x5001		Lid closed | 
 | 0x5002		Lid opened | 
 | 0x7000		Radio Switch may have changed state | 
 |  | 
 | The above events are not propagated by the driver, except for legacy | 
 | compatibility purposes when hotkey_report_mode is set to 1. | 
 |  | 
 | Compatibility notes: | 
 |  | 
 | ibm-acpi and thinkpad-acpi 0.15 (mainline kernels before 2.6.23) never | 
 | supported the input layer, and sent events over the procfs ACPI event | 
 | interface. | 
 |  | 
 | To avoid sending duplicate events over the input layer and the ACPI | 
 | event interface, thinkpad-acpi 0.16 implements a module parameter | 
 | (hotkey_report_mode), and also a sysfs device attribute with the same | 
 | name. | 
 |  | 
 | Make no mistake here: userspace is expected to switch to using the input | 
 | layer interface of thinkpad-acpi, together with the ACPI netlink event | 
 | interface in kernels 2.6.23 and later, or with the ACPI procfs event | 
 | interface in kernels 2.6.22 and earlier. | 
 |  | 
 | If no hotkey_report_mode module parameter is specified (or it is set to | 
 | zero), the driver defaults to mode 1 (see below), and on kernels 2.6.22 | 
 | and earlier, also allows one to change the hotkey_report_mode through | 
 | sysfs.  In kernels 2.6.23 and later, where the netlink ACPI event | 
 | interface is available, hotkey_report_mode cannot be changed through | 
 | sysfs (it is read-only). | 
 |  | 
 | If the hotkey_report_mode module parameter is set to 1 or 2, it cannot | 
 | be changed later through sysfs (any writes will return -EPERM to signal | 
 | that hotkey_report_mode was locked.  On 2.6.23 and later, where | 
 | hotkey_report_mode cannot be changed at all, writes will return -EACES). | 
 |  | 
 | hotkey_report_mode set to 1 makes the driver export through the procfs | 
 | ACPI event interface all hot key presses (which are *also* sent to the | 
 | input layer).  This is a legacy compatibility behaviour, and it is also | 
 | the default mode of operation for the driver. | 
 |  | 
 | hotkey_report_mode set to 2 makes the driver filter out the hot key | 
 | presses from the procfs ACPI event interface, so these events will only | 
 | be sent through the input layer.  Userspace that has been updated to use | 
 | the thinkpad-acpi input layer interface should set hotkey_report_mode to | 
 | 2. | 
 |  | 
 | Hot key press events are never sent to the ACPI netlink event interface. | 
 | Really up-to-date userspace under kernel 2.6.23 and later is to use the | 
 | netlink interface and the input layer interface, and don't bother at all | 
 | with hotkey_report_mode. | 
 |  | 
 |  | 
 | Bluetooth | 
 | --------- | 
 |  | 
 | procfs: /proc/acpi/ibm/bluetooth | 
 | sysfs device attribute: bluetooth_enable | 
 |  | 
 | This feature shows the presence and current state of a ThinkPad | 
 | Bluetooth device in the internal ThinkPad CDC slot. | 
 |  | 
 | Procfs notes: | 
 |  | 
 | If Bluetooth is installed, the following commands can be used: | 
 |  | 
 | 	echo enable > /proc/acpi/ibm/bluetooth | 
 | 	echo disable > /proc/acpi/ibm/bluetooth | 
 |  | 
 | Sysfs notes: | 
 |  | 
 | 	If the Bluetooth CDC card is installed, it can be enabled / | 
 | 	disabled through the "bluetooth_enable" thinkpad-acpi device | 
 | 	attribute, and its current status can also be queried. | 
 |  | 
 | 	enable: | 
 | 		0: disables Bluetooth / Bluetooth is disabled | 
 | 		1: enables Bluetooth / Bluetooth is enabled. | 
 |  | 
 | 	Note: this interface will be probably be superseeded by the | 
 | 	generic rfkill class, so it is NOT to be considered stable yet. | 
 |  | 
 | Video output control -- /proc/acpi/ibm/video | 
 | -------------------------------------------- | 
 |  | 
 | This feature allows control over the devices used for video output - | 
 | LCD, CRT or DVI (if available). The following commands are available: | 
 |  | 
 | 	echo lcd_enable > /proc/acpi/ibm/video | 
 | 	echo lcd_disable > /proc/acpi/ibm/video | 
 | 	echo crt_enable > /proc/acpi/ibm/video | 
 | 	echo crt_disable > /proc/acpi/ibm/video | 
 | 	echo dvi_enable > /proc/acpi/ibm/video | 
 | 	echo dvi_disable > /proc/acpi/ibm/video | 
 | 	echo auto_enable > /proc/acpi/ibm/video | 
 | 	echo auto_disable > /proc/acpi/ibm/video | 
 | 	echo expand_toggle > /proc/acpi/ibm/video | 
 | 	echo video_switch > /proc/acpi/ibm/video | 
 |  | 
 | Each video output device can be enabled or disabled individually. | 
 | Reading /proc/acpi/ibm/video shows the status of each device. | 
 |  | 
 | Automatic video switching can be enabled or disabled.  When automatic | 
 | video switching is enabled, certain events (e.g. opening the lid, | 
 | docking or undocking) cause the video output device to change | 
 | automatically. While this can be useful, it also causes flickering | 
 | and, on the X40, video corruption. By disabling automatic switching, | 
 | the flickering or video corruption can be avoided. | 
 |  | 
 | The video_switch command cycles through the available video outputs | 
 | (it simulates the behavior of Fn-F7). | 
 |  | 
 | Video expansion can be toggled through this feature. This controls | 
 | whether the display is expanded to fill the entire LCD screen when a | 
 | mode with less than full resolution is used. Note that the current | 
 | video expansion status cannot be determined through this feature. | 
 |  | 
 | Note that on many models (particularly those using Radeon graphics | 
 | chips) the X driver configures the video card in a way which prevents | 
 | Fn-F7 from working. This also disables the video output switching | 
 | features of this driver, as it uses the same ACPI methods as | 
 | Fn-F7. Video switching on the console should still work. | 
 |  | 
 | UPDATE: There's now a patch for the X.org Radeon driver which | 
 | addresses this issue. Some people are reporting success with the patch | 
 | while others are still having problems. For more information: | 
 |  | 
 | https://bugs.freedesktop.org/show_bug.cgi?id=2000 | 
 |  | 
 | ThinkLight control -- /proc/acpi/ibm/light | 
 | ------------------------------------------ | 
 |  | 
 | The current status of the ThinkLight can be found in this file. A few | 
 | models which do not make the status available will show it as | 
 | "unknown". The available commands are: | 
 |  | 
 | 	echo on  > /proc/acpi/ibm/light | 
 | 	echo off > /proc/acpi/ibm/light | 
 |  | 
 | Docking / undocking -- /proc/acpi/ibm/dock | 
 | ------------------------------------------ | 
 |  | 
 | Docking and undocking (e.g. with the X4 UltraBase) requires some | 
 | actions to be taken by the operating system to safely make or break | 
 | the electrical connections with the dock. | 
 |  | 
 | The docking feature of this driver generates the following ACPI events: | 
 |  | 
 | 	ibm/dock GDCK 00000003 00000001 -- eject request | 
 | 	ibm/dock GDCK 00000003 00000002 -- undocked | 
 | 	ibm/dock GDCK 00000000 00000003 -- docked | 
 |  | 
 | NOTE: These events will only be generated if the laptop was docked | 
 | when originally booted. This is due to the current lack of support for | 
 | hot plugging of devices in the Linux ACPI framework. If the laptop was | 
 | booted while not in the dock, the following message is shown in the | 
 | logs: | 
 |  | 
 | 	Mar 17 01:42:34 aero kernel: thinkpad_acpi: dock device not present | 
 |  | 
 | In this case, no dock-related events are generated but the dock and | 
 | undock commands described below still work. They can be executed | 
 | manually or triggered by Fn key combinations (see the example acpid | 
 | configuration files included in the driver tarball package available | 
 | on the web site). | 
 |  | 
 | When the eject request button on the dock is pressed, the first event | 
 | above is generated. The handler for this event should issue the | 
 | following command: | 
 |  | 
 | 	echo undock > /proc/acpi/ibm/dock | 
 |  | 
 | After the LED on the dock goes off, it is safe to eject the laptop. | 
 | Note: if you pressed this key by mistake, go ahead and eject the | 
 | laptop, then dock it back in. Otherwise, the dock may not function as | 
 | expected. | 
 |  | 
 | When the laptop is docked, the third event above is generated. The | 
 | handler for this event should issue the following command to fully | 
 | enable the dock: | 
 |  | 
 | 	echo dock > /proc/acpi/ibm/dock | 
 |  | 
 | The contents of the /proc/acpi/ibm/dock file shows the current status | 
 | of the dock, as provided by the ACPI framework. | 
 |  | 
 | The docking support in this driver does not take care of enabling or | 
 | disabling any other devices you may have attached to the dock. For | 
 | example, a CD drive plugged into the UltraBase needs to be disabled or | 
 | enabled separately. See the provided example acpid configuration files | 
 | for how this can be accomplished. | 
 |  | 
 | There is no support yet for PCI devices that may be attached to a | 
 | docking station, e.g. in the ThinkPad Dock II. The driver currently | 
 | does not recognize, enable or disable such devices. This means that | 
 | the only docking stations currently supported are the X-series | 
 | UltraBase docks and "dumb" port replicators like the Mini Dock (the | 
 | latter don't need any ACPI support, actually). | 
 |  | 
 | UltraBay eject -- /proc/acpi/ibm/bay | 
 | ------------------------------------ | 
 |  | 
 | Inserting or ejecting an UltraBay device requires some actions to be | 
 | taken by the operating system to safely make or break the electrical | 
 | connections with the device. | 
 |  | 
 | This feature generates the following ACPI events: | 
 |  | 
 | 	ibm/bay MSTR 00000003 00000000 -- eject request | 
 | 	ibm/bay MSTR 00000001 00000000 -- eject lever inserted | 
 |  | 
 | NOTE: These events will only be generated if the UltraBay was present | 
 | when the laptop was originally booted (on the X series, the UltraBay | 
 | is in the dock, so it may not be present if the laptop was undocked). | 
 | This is due to the current lack of support for hot plugging of devices | 
 | in the Linux ACPI framework. If the laptop was booted without the | 
 | UltraBay, the following message is shown in the logs: | 
 |  | 
 | 	Mar 17 01:42:34 aero kernel: thinkpad_acpi: bay device not present | 
 |  | 
 | In this case, no bay-related events are generated but the eject | 
 | command described below still works. It can be executed manually or | 
 | triggered by a hot key combination. | 
 |  | 
 | Sliding the eject lever generates the first event shown above. The | 
 | handler for this event should take whatever actions are necessary to | 
 | shut down the device in the UltraBay (e.g. call idectl), then issue | 
 | the following command: | 
 |  | 
 | 	echo eject > /proc/acpi/ibm/bay | 
 |  | 
 | After the LED on the UltraBay goes off, it is safe to pull out the | 
 | device. | 
 |  | 
 | When the eject lever is inserted, the second event above is | 
 | generated. The handler for this event should take whatever actions are | 
 | necessary to enable the UltraBay device (e.g. call idectl). | 
 |  | 
 | The contents of the /proc/acpi/ibm/bay file shows the current status | 
 | of the UltraBay, as provided by the ACPI framework. | 
 |  | 
 | EXPERIMENTAL warm eject support on the 600e/x, A22p and A3x (To use | 
 | this feature, you need to supply the experimental=1 parameter when | 
 | loading the module): | 
 |  | 
 | These models do not have a button near the UltraBay device to request | 
 | a hot eject but rather require the laptop to be put to sleep | 
 | (suspend-to-ram) before the bay device is ejected or inserted). | 
 | The sequence of steps to eject the device is as follows: | 
 |  | 
 | 	echo eject > /proc/acpi/ibm/bay | 
 | 	put the ThinkPad to sleep | 
 | 	remove the drive | 
 | 	resume from sleep | 
 | 	cat /proc/acpi/ibm/bay should show that the drive was removed | 
 |  | 
 | On the A3x, both the UltraBay 2000 and UltraBay Plus devices are | 
 | supported. Use "eject2" instead of "eject" for the second bay. | 
 |  | 
 | Note: the UltraBay eject support on the 600e/x, A22p and A3x is | 
 | EXPERIMENTAL and may not work as expected. USE WITH CAUTION! | 
 |  | 
 | CMOS control | 
 | ------------ | 
 |  | 
 | procfs: /proc/acpi/ibm/cmos | 
 | sysfs device attribute: cmos_command | 
 |  | 
 | This feature is mostly used internally by the ACPI firmware to keep the legacy | 
 | CMOS NVRAM bits in sync with the current machine state, and to record this | 
 | state so that the ThinkPad will retain such settings across reboots. | 
 |  | 
 | Some of these commands actually perform actions in some ThinkPad models, but | 
 | this is expected to disappear more and more in newer models.  As an example, in | 
 | a T43 and in a X40, commands 12 and 13 still control the ThinkLight state for | 
 | real, but commands 0 to 2 don't control the mixer anymore (they have been | 
 | phased out) and just update the NVRAM. | 
 |  | 
 | The range of valid cmos command numbers is 0 to 21, but not all have an | 
 | effect and the behavior varies from model to model.  Here is the behavior | 
 | on the X40 (tpb is the ThinkPad Buttons utility): | 
 |  | 
 | 	0 - Related to "Volume down" key press | 
 | 	1 - Related to "Volume up" key press | 
 | 	2 - Related to "Mute on" key press | 
 | 	3 - Related to "Access IBM" key press | 
 | 	4 - Related to "LCD brightness up" key pess | 
 | 	5 - Related to "LCD brightness down" key press | 
 | 	11 - Related to "toggle screen expansion" key press/function | 
 | 	12 - Related to "ThinkLight on" | 
 | 	13 - Related to "ThinkLight off" | 
 | 	14 - Related to "ThinkLight" key press (toggle thinklight) | 
 |  | 
 | The cmos command interface is prone to firmware split-brain problems, as | 
 | in newer ThinkPads it is just a compatibility layer.  Do not use it, it is | 
 | exported just as a debug tool. | 
 |  | 
 | LED control -- /proc/acpi/ibm/led | 
 | --------------------------------- | 
 |  | 
 | Some of the LED indicators can be controlled through this feature. The | 
 | available commands are: | 
 |  | 
 | 	echo '<led number> on' >/proc/acpi/ibm/led | 
 | 	echo '<led number> off' >/proc/acpi/ibm/led | 
 | 	echo '<led number> blink' >/proc/acpi/ibm/led | 
 |  | 
 | The <led number> range is 0 to 7. The set of LEDs that can be | 
 | controlled varies from model to model. Here is the mapping on the X40: | 
 |  | 
 | 	0 - power | 
 | 	1 - battery (orange) | 
 | 	2 - battery (green) | 
 | 	3 - UltraBase | 
 | 	4 - UltraBay | 
 | 	7 - standby | 
 |  | 
 | All of the above can be turned on and off and can be made to blink. | 
 |  | 
 | ACPI sounds -- /proc/acpi/ibm/beep | 
 | ---------------------------------- | 
 |  | 
 | The BEEP method is used internally by the ACPI firmware to provide | 
 | audible alerts in various situations. This feature allows the same | 
 | sounds to be triggered manually. | 
 |  | 
 | The commands are non-negative integer numbers: | 
 |  | 
 | 	echo <number> >/proc/acpi/ibm/beep | 
 |  | 
 | The valid <number> range is 0 to 17. Not all numbers trigger sounds | 
 | and the sounds vary from model to model. Here is the behavior on the | 
 | X40: | 
 |  | 
 | 	0 - stop a sound in progress (but use 17 to stop 16) | 
 | 	2 - two beeps, pause, third beep ("low battery") | 
 | 	3 - single beep | 
 | 	4 - high, followed by low-pitched beep ("unable") | 
 | 	5 - single beep | 
 | 	6 - very high, followed by high-pitched beep ("AC/DC") | 
 | 	7 - high-pitched beep | 
 | 	9 - three short beeps | 
 | 	10 - very long beep | 
 | 	12 - low-pitched beep | 
 | 	15 - three high-pitched beeps repeating constantly, stop with 0 | 
 | 	16 - one medium-pitched beep repeating constantly, stop with 17 | 
 | 	17 - stop 16 | 
 |  | 
 | Temperature sensors | 
 | ------------------- | 
 |  | 
 | procfs: /proc/acpi/ibm/thermal | 
 | sysfs device attributes: (hwmon "thinkpad") temp*_input | 
 |  | 
 | Most ThinkPads include six or more separate temperature sensors but only | 
 | expose the CPU temperature through the standard ACPI methods.  This | 
 | feature shows readings from up to eight different sensors on older | 
 | ThinkPads, and up to sixteen different sensors on newer ThinkPads. | 
 |  | 
 | For example, on the X40, a typical output may be: | 
 | temperatures:   42 42 45 41 36 -128 33 -128 | 
 |  | 
 | On the T43/p, a typical output may be: | 
 | temperatures:   48 48 36 52 38 -128 31 -128 48 52 48 -128 -128 -128 -128 -128 | 
 |  | 
 | The mapping of thermal sensors to physical locations varies depending on | 
 | system-board model (and thus, on ThinkPad model). | 
 |  | 
 | http://thinkwiki.org/wiki/Thermal_Sensors is a public wiki page that | 
 | tries to track down these locations for various models. | 
 |  | 
 | Most (newer?) models seem to follow this pattern: | 
 |  | 
 | 1:  CPU | 
 | 2:  (depends on model) | 
 | 3:  (depends on model) | 
 | 4:  GPU | 
 | 5:  Main battery: main sensor | 
 | 6:  Bay battery: main sensor | 
 | 7:  Main battery: secondary sensor | 
 | 8:  Bay battery: secondary sensor | 
 | 9-15: (depends on model) | 
 |  | 
 | For the R51 (source: Thomas Gruber): | 
 | 2:  Mini-PCI | 
 | 3:  Internal HDD | 
 |  | 
 | For the T43, T43/p (source: Shmidoax/Thinkwiki.org) | 
 | http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_T43.2C_T43p | 
 | 2:  System board, left side (near PCMCIA slot), reported as HDAPS temp | 
 | 3:  PCMCIA slot | 
 | 9:  MCH (northbridge) to DRAM Bus | 
 | 10: Clock-generator, mini-pci card and ICH (southbridge), under Mini-PCI | 
 |     card, under touchpad | 
 | 11: Power regulator, underside of system board, below F2 key | 
 |  | 
 | The A31 has a very atypical layout for the thermal sensors | 
 | (source: Milos Popovic, http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_A31) | 
 | 1:  CPU | 
 | 2:  Main Battery: main sensor | 
 | 3:  Power Converter | 
 | 4:  Bay Battery: main sensor | 
 | 5:  MCH (northbridge) | 
 | 6:  PCMCIA/ambient | 
 | 7:  Main Battery: secondary sensor | 
 | 8:  Bay Battery: secondary sensor | 
 |  | 
 |  | 
 | Procfs notes: | 
 | 	Readings from sensors that are not available return -128. | 
 | 	No commands can be written to this file. | 
 |  | 
 | Sysfs notes: | 
 | 	Sensors that are not available return the ENXIO error.  This | 
 | 	status may change at runtime, as there are hotplug thermal | 
 | 	sensors, like those inside the batteries and docks. | 
 |  | 
 | 	thinkpad-acpi thermal sensors are reported through the hwmon | 
 | 	subsystem, and follow all of the hwmon guidelines at | 
 | 	Documentation/hwmon. | 
 |  | 
 |  | 
 | EXPERIMENTAL: Embedded controller register dump -- /proc/acpi/ibm/ecdump | 
 | ------------------------------------------------------------------------ | 
 |  | 
 | This feature is marked EXPERIMENTAL because the implementation | 
 | directly accesses hardware registers and may not work as expected. USE | 
 | WITH CAUTION! To use this feature, you need to supply the | 
 | experimental=1 parameter when loading the module. | 
 |  | 
 | This feature dumps the values of 256 embedded controller | 
 | registers. Values which have changed since the last time the registers | 
 | were dumped are marked with a star: | 
 |  | 
 | [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump | 
 | EC       +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f | 
 | EC 0x00:  a7  47  87  01  fe  96  00  08  01  00  cb  00  00  00  40  00 | 
 | EC 0x10:  00  00  ff  ff  f4  3c  87  09  01  ff  42  01  ff  ff  0d  00 | 
 | EC 0x20:  00  00  00  00  00  00  00  00  00  00  00  03  43  00  00  80 | 
 | EC 0x30:  01  07  1a  00  30  04  00  00 *85  00  00  10  00  50  00  00 | 
 | EC 0x40:  00  00  00  00  00  00  14  01  00  04  00  00  00  00  00  00 | 
 | EC 0x50:  00  c0  02  0d  00  01  01  02  02  03  03  03  03 *bc *02 *bc | 
 | EC 0x60: *02 *bc *02  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0x70:  00  00  00  00  00  12  30  40 *24 *26 *2c *27 *20  80 *1f  80 | 
 | EC 0x80:  00  00  00  06 *37 *0e  03  00  00  00  0e  07  00  00  00  00 | 
 | EC 0x90:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xa0: *ff  09  ff  09  ff  ff *64  00 *00 *00 *a2  41 *ff *ff *e0  00 | 
 | EC 0xb0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xc0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xd0:  03  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xe0:  00  00  00  00  00  00  00  00  11  20  49  04  24  06  55  03 | 
 | EC 0xf0:  31  55  48  54  35  38  57  57  08  2f  45  73  07  65  6c  1a | 
 |  | 
 | This feature can be used to determine the register holding the fan | 
 | speed on some models. To do that, do the following: | 
 |  | 
 | 	- make sure the battery is fully charged | 
 | 	- make sure the fan is running | 
 | 	- run 'cat /proc/acpi/ibm/ecdump' several times, once per second or so | 
 |  | 
 | The first step makes sure various charging-related values don't | 
 | vary. The second ensures that the fan-related values do vary, since | 
 | the fan speed fluctuates a bit. The third will (hopefully) mark the | 
 | fan register with a star: | 
 |  | 
 | [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump | 
 | EC       +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f | 
 | EC 0x00:  a7  47  87  01  fe  96  00  08  01  00  cb  00  00  00  40  00 | 
 | EC 0x10:  00  00  ff  ff  f4  3c  87  09  01  ff  42  01  ff  ff  0d  00 | 
 | EC 0x20:  00  00  00  00  00  00  00  00  00  00  00  03  43  00  00  80 | 
 | EC 0x30:  01  07  1a  00  30  04  00  00  85  00  00  10  00  50  00  00 | 
 | EC 0x40:  00  00  00  00  00  00  14  01  00  04  00  00  00  00  00  00 | 
 | EC 0x50:  00  c0  02  0d  00  01  01  02  02  03  03  03  03  bc  02  bc | 
 | EC 0x60:  02  bc  02  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0x70:  00  00  00  00  00  12  30  40  24  27  2c  27  21  80  1f  80 | 
 | EC 0x80:  00  00  00  06 *be  0d  03  00  00  00  0e  07  00  00  00  00 | 
 | EC 0x90:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xa0:  ff  09  ff  09  ff  ff  64  00  00  00  a2  41  ff  ff  e0  00 | 
 | EC 0xb0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xc0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xd0:  03  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00 | 
 | EC 0xe0:  00  00  00  00  00  00  00  00  11  20  49  04  24  06  55  03 | 
 | EC 0xf0:  31  55  48  54  35  38  57  57  08  2f  45  73  07  65  6c  1a | 
 |  | 
 | Another set of values that varies often is the temperature | 
 | readings. Since temperatures don't change vary fast, you can take | 
 | several quick dumps to eliminate them. | 
 |  | 
 | You can use a similar method to figure out the meaning of other | 
 | embedded controller registers - e.g. make sure nothing else changes | 
 | except the charging or discharging battery to determine which | 
 | registers contain the current battery capacity, etc. If you experiment | 
 | with this, do send me your results (including some complete dumps with | 
 | a description of the conditions when they were taken.) | 
 |  | 
 | LCD brightness control | 
 | ---------------------- | 
 |  | 
 | procfs: /proc/acpi/ibm/brightness | 
 | sysfs backlight device "thinkpad_screen" | 
 |  | 
 | This feature allows software control of the LCD brightness on ThinkPad | 
 | models which don't have a hardware brightness slider. | 
 |  | 
 | It has some limitations: the LCD backlight cannot be actually turned on or off | 
 | by this interface, and in many ThinkPad models, the "dim while on battery" | 
 | functionality will be enabled by the BIOS when this interface is used, and | 
 | cannot be controlled. | 
 |  | 
 | The backlight control has eight levels, ranging from 0 to 7.  Some of the | 
 | levels may not be distinct. | 
 |  | 
 | There are two interfaces to the firmware for brightness control, EC and CMOS. | 
 | To select which one should be used, use the brightness_mode module parameter: | 
 | brightness_mode=1 selects EC mode, brightness_mode=2 selects CMOS mode, | 
 | brightness_mode=3 selects both EC and CMOS.  The driver tries to autodetect | 
 | which interface to use. | 
 |  | 
 | Procfs notes: | 
 |  | 
 | 	The available commands are: | 
 |  | 
 | 	echo up   >/proc/acpi/ibm/brightness | 
 | 	echo down >/proc/acpi/ibm/brightness | 
 | 	echo 'level <level>' >/proc/acpi/ibm/brightness | 
 |  | 
 | Sysfs notes: | 
 |  | 
 | The interface is implemented through the backlight sysfs class, which is poorly | 
 | documented at this time. | 
 |  | 
 | Locate the thinkpad_screen device under /sys/class/backlight, and inside it | 
 | there will be the following attributes: | 
 |  | 
 | 	max_brightness: | 
 | 		Reads the maximum brightness the hardware can be set to. | 
 | 		The minimum is always zero. | 
 |  | 
 | 	actual_brightness: | 
 | 		Reads what brightness the screen is set to at this instant. | 
 |  | 
 | 	brightness: | 
 | 		Writes request the driver to change brightness to the given | 
 | 		value.  Reads will tell you what brightness the driver is trying | 
 | 		to set the display to when "power" is set to zero and the display | 
 | 		has not been dimmed by a kernel power management event. | 
 |  | 
 | 	power: | 
 | 		power management mode, where 0 is "display on", and 1 to 3 will | 
 | 		dim the display backlight to brightness level 0 because | 
 | 		thinkpad-acpi cannot really turn the backlight off.  Kernel | 
 | 		power management events can temporarily increase the current | 
 | 		power management level, i.e. they can dim the display. | 
 |  | 
 |  | 
 | Volume control -- /proc/acpi/ibm/volume | 
 | --------------------------------------- | 
 |  | 
 | This feature allows volume control on ThinkPad models which don't have | 
 | a hardware volume knob. The available commands are: | 
 |  | 
 | 	echo up   >/proc/acpi/ibm/volume | 
 | 	echo down >/proc/acpi/ibm/volume | 
 | 	echo mute >/proc/acpi/ibm/volume | 
 | 	echo 'level <level>' >/proc/acpi/ibm/volume | 
 |  | 
 | The <level> number range is 0 to 15 although not all of them may be | 
 | distinct. The unmute the volume after the mute command, use either the | 
 | up or down command (the level command will not unmute the volume). | 
 | The current volume level and mute state is shown in the file. | 
 |  | 
 | Fan control and monitoring: fan speed, fan enable/disable | 
 | --------------------------------------------------------- | 
 |  | 
 | procfs: /proc/acpi/ibm/fan | 
 | sysfs device attributes: (hwmon "thinkpad") fan1_input, pwm1, | 
 | 			  pwm1_enable | 
 | sysfs hwmon driver attributes: fan_watchdog | 
 |  | 
 | NOTE NOTE NOTE: fan control operations are disabled by default for | 
 | safety reasons.  To enable them, the module parameter "fan_control=1" | 
 | must be given to thinkpad-acpi. | 
 |  | 
 | This feature attempts to show the current fan speed, control mode and | 
 | other fan data that might be available.  The speed is read directly | 
 | from the hardware registers of the embedded controller.  This is known | 
 | to work on later R, T, X and Z series ThinkPads but may show a bogus | 
 | value on other models. | 
 |  | 
 | Fan levels: | 
 |  | 
 | Most ThinkPad fans work in "levels" at the firmware interface.  Level 0 | 
 | stops the fan.  The higher the level, the higher the fan speed, although | 
 | adjacent levels often map to the same fan speed.  7 is the highest | 
 | level, where the fan reaches the maximum recommended speed. | 
 |  | 
 | Level "auto" means the EC changes the fan level according to some | 
 | internal algorithm, usually based on readings from the thermal sensors. | 
 |  | 
 | There is also a "full-speed" level, also known as "disengaged" level. | 
 | In this level, the EC disables the speed-locked closed-loop fan control, | 
 | and drives the fan as fast as it can go, which might exceed hardware | 
 | limits, so use this level with caution. | 
 |  | 
 | The fan usually ramps up or down slowly from one speed to another, and | 
 | it is normal for the EC to take several seconds to react to fan | 
 | commands.  The full-speed level may take up to two minutes to ramp up to | 
 | maximum speed, and in some ThinkPads, the tachometer readings go stale | 
 | while the EC is transitioning to the full-speed level. | 
 |  | 
 | WARNING WARNING WARNING: do not leave the fan disabled unless you are | 
 | monitoring all of the temperature sensor readings and you are ready to | 
 | enable it if necessary to avoid overheating. | 
 |  | 
 | An enabled fan in level "auto" may stop spinning if the EC decides the | 
 | ThinkPad is cool enough and doesn't need the extra airflow.  This is | 
 | normal, and the EC will spin the fan up if the various thermal readings | 
 | rise too much. | 
 |  | 
 | On the X40, this seems to depend on the CPU and HDD temperatures. | 
 | Specifically, the fan is turned on when either the CPU temperature | 
 | climbs to 56 degrees or the HDD temperature climbs to 46 degrees.  The | 
 | fan is turned off when the CPU temperature drops to 49 degrees and the | 
 | HDD temperature drops to 41 degrees.  These thresholds cannot | 
 | currently be controlled. | 
 |  | 
 | The ThinkPad's ACPI DSDT code will reprogram the fan on its own when | 
 | certain conditions are met.  It will override any fan programming done | 
 | through thinkpad-acpi. | 
 |  | 
 | The thinkpad-acpi kernel driver can be programmed to revert the fan | 
 | level to a safe setting if userspace does not issue one of the procfs | 
 | fan commands: "enable", "disable", "level" or "watchdog", or if there | 
 | are no writes to pwm1_enable (or to pwm1 *if and only if* pwm1_enable is | 
 | set to 1, manual mode) within a configurable amount of time of up to | 
 | 120 seconds.  This functionality is called fan safety watchdog. | 
 |  | 
 | Note that the watchdog timer stops after it enables the fan.  It will be | 
 | rearmed again automatically (using the same interval) when one of the | 
 | above mentioned fan commands is received.  The fan watchdog is, | 
 | therefore, not suitable to protect against fan mode changes made through | 
 | means other than the "enable", "disable", and "level" procfs fan | 
 | commands, or the hwmon fan control sysfs interface. | 
 |  | 
 | Procfs notes: | 
 |  | 
 | The fan may be enabled or disabled with the following commands: | 
 |  | 
 | 	echo enable  >/proc/acpi/ibm/fan | 
 | 	echo disable >/proc/acpi/ibm/fan | 
 |  | 
 | Placing a fan on level 0 is the same as disabling it.  Enabling a fan | 
 | will try to place it in a safe level if it is too slow or disabled. | 
 |  | 
 | The fan level can be controlled with the command: | 
 |  | 
 | 	echo 'level <level>' > /proc/acpi/ibm/fan | 
 |  | 
 | Where <level> is an integer from 0 to 7, or one of the words "auto" or | 
 | "full-speed" (without the quotes).  Not all ThinkPads support the "auto" | 
 | and "full-speed" levels.  The driver accepts "disengaged" as an alias for | 
 | "full-speed", and reports it as "disengaged" for backwards | 
 | compatibility. | 
 |  | 
 | On the X31 and X40 (and ONLY on those models), the fan speed can be | 
 | controlled to a certain degree.  Once the fan is running, it can be | 
 | forced to run faster or slower with the following command: | 
 |  | 
 | 	echo 'speed <speed>' > /proc/acpi/ibm/fan | 
 |  | 
 | The sustainable range of fan speeds on the X40 appears to be from about | 
 | 3700 to about 7350. Values outside this range either do not have any | 
 | effect or the fan speed eventually settles somewhere in that range.  The | 
 | fan cannot be stopped or started with this command.  This functionality | 
 | is incomplete, and not available through the sysfs interface. | 
 |  | 
 | To program the safety watchdog, use the "watchdog" command. | 
 |  | 
 | 	echo 'watchdog <interval in seconds>' > /proc/acpi/ibm/fan | 
 |  | 
 | If you want to disable the watchdog, use 0 as the interval. | 
 |  | 
 | Sysfs notes: | 
 |  | 
 | The sysfs interface follows the hwmon subsystem guidelines for the most | 
 | part, and the exception is the fan safety watchdog. | 
 |  | 
 | Writes to any of the sysfs attributes may return the EINVAL error if | 
 | that operation is not supported in a given ThinkPad or if the parameter | 
 | is out-of-bounds, and EPERM if it is forbidden.  They may also return | 
 | EINTR (interrupted system call), and EIO (I/O error while trying to talk | 
 | to the firmware). | 
 |  | 
 | Features not yet implemented by the driver return ENOSYS. | 
 |  | 
 | hwmon device attribute pwm1_enable: | 
 | 	0: PWM offline (fan is set to full-speed mode) | 
 | 	1: Manual PWM control (use pwm1 to set fan level) | 
 | 	2: Hardware PWM control (EC "auto" mode) | 
 | 	3: reserved (Software PWM control, not implemented yet) | 
 |  | 
 | 	Modes 0 and 2 are not supported by all ThinkPads, and the | 
 | 	driver is not always able to detect this.  If it does know a | 
 | 	mode is unsupported, it will return -EINVAL. | 
 |  | 
 | hwmon device attribute pwm1: | 
 | 	Fan level, scaled from the firmware values of 0-7 to the hwmon | 
 | 	scale of 0-255.  0 means fan stopped, 255 means highest normal | 
 | 	speed (level 7). | 
 |  | 
 | 	This attribute only commands the fan if pmw1_enable is set to 1 | 
 | 	(manual PWM control). | 
 |  | 
 | hwmon device attribute fan1_input: | 
 | 	Fan tachometer reading, in RPM.  May go stale on certain | 
 | 	ThinkPads while the EC transitions the PWM to offline mode, | 
 | 	which can take up to two minutes.  May return rubbish on older | 
 | 	ThinkPads. | 
 |  | 
 | hwmon driver attribute fan_watchdog: | 
 | 	Fan safety watchdog timer interval, in seconds.  Minimum is | 
 | 	1 second, maximum is 120 seconds.  0 disables the watchdog. | 
 |  | 
 | To stop the fan: set pwm1 to zero, and pwm1_enable to 1. | 
 |  | 
 | To start the fan in a safe mode: set pwm1_enable to 2.  If that fails | 
 | with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255 | 
 | would be the safest choice, though). | 
 |  | 
 |  | 
 | EXPERIMENTAL: WAN | 
 | ----------------- | 
 |  | 
 | procfs: /proc/acpi/ibm/wan | 
 | sysfs device attribute: wwan_enable | 
 |  | 
 | This feature is marked EXPERIMENTAL because the implementation | 
 | directly accesses hardware registers and may not work as expected. USE | 
 | WITH CAUTION! To use this feature, you need to supply the | 
 | experimental=1 parameter when loading the module. | 
 |  | 
 | This feature shows the presence and current state of a W-WAN (Sierra | 
 | Wireless EV-DO) device. | 
 |  | 
 | It was tested on a Lenovo Thinkpad X60. It should probably work on other | 
 | Thinkpad models which come with this module installed. | 
 |  | 
 | Procfs notes: | 
 |  | 
 | If the W-WAN card is installed, the following commands can be used: | 
 |  | 
 | 	echo enable > /proc/acpi/ibm/wan | 
 | 	echo disable > /proc/acpi/ibm/wan | 
 |  | 
 | Sysfs notes: | 
 |  | 
 | 	If the W-WAN card is installed, it can be enabled / | 
 | 	disabled through the "wwan_enable" thinkpad-acpi device | 
 | 	attribute, and its current status can also be queried. | 
 |  | 
 | 	enable: | 
 | 		0: disables WWAN card / WWAN card is disabled | 
 | 		1: enables WWAN card / WWAN card is enabled. | 
 |  | 
 | 	Note: this interface will be probably be superseeded by the | 
 | 	generic rfkill class, so it is NOT to be considered stable yet. | 
 |  | 
 | Multiple Commands, Module Parameters | 
 | ------------------------------------ | 
 |  | 
 | Multiple commands can be written to the proc files in one shot by | 
 | separating them with commas, for example: | 
 |  | 
 | 	echo enable,0xffff > /proc/acpi/ibm/hotkey | 
 | 	echo lcd_disable,crt_enable > /proc/acpi/ibm/video | 
 |  | 
 | Commands can also be specified when loading the thinkpad-acpi module, | 
 | for example: | 
 |  | 
 | 	modprobe thinkpad_acpi hotkey=enable,0xffff video=auto_disable | 
 |  | 
 | Enabling debugging output | 
 | ------------------------- | 
 |  | 
 | The module takes a debug parameter which can be used to selectively | 
 | enable various classes of debugging output, for example: | 
 |  | 
 | 	 modprobe ibm_acpi debug=0xffff | 
 |  | 
 | will enable all debugging output classes.  It takes a bitmask, so | 
 | to enable more than one output class, just add their values. | 
 |  | 
 | 	Debug bitmask		Description | 
 | 	0x0001			Initialization and probing | 
 | 	0x0002			Removal | 
 |  | 
 | There is also a kernel build option to enable more debugging | 
 | information, which may be necessary to debug driver problems. | 
 |  | 
 | The level of debugging information output by the driver can be changed | 
 | at runtime through sysfs, using the driver attribute debug_level.  The | 
 | attribute takes the same bitmask as the debug module parameter above. | 
 |  | 
 | Force loading of module | 
 | ----------------------- | 
 |  | 
 | If thinkpad-acpi refuses to detect your ThinkPad, you can try to specify | 
 | the module parameter force_load=1.  Regardless of whether this works or | 
 | not, please contact ibm-acpi-devel@lists.sourceforge.net with a report. | 
 |  | 
 |  | 
 | Sysfs interface changelog: | 
 |  | 
 | 0x000100:	Initial sysfs support, as a single platform driver and | 
 | 		device. | 
 | 0x000200:	Hot key support for 32 hot keys, and radio slider switch | 
 | 		support. | 
 | 0x010000:	Hot keys are now handled by default over the input | 
 | 		layer, the radio switch generates input event EV_RADIO, | 
 | 		and the driver enables hot key handling by default in | 
 | 		the firmware. | 
 |  | 
 | 0x020000:	ABI fix: added a separate hwmon platform device and | 
 | 		driver, which must be located by name (thinkpad) | 
 | 		and the hwmon class for libsensors4 (lm-sensors 3) | 
 | 		compatibility.  Moved all hwmon attributes to this | 
 | 		new platform device. |