1 ThinkPad ACPI Extras Driver
6 Borislav Deianov <borislav@users.sf.net>
7 Henrique de Moraes Holschuh <hmh@hmh.eng.br>
8 http://ibm-acpi.sf.net/
11 This is a Linux driver for the IBM and Lenovo ThinkPad laptops. It
12 supports various features of these laptops which are accessible
13 through the ACPI and ACPI EC framework, but not otherwise fully
14 supported by the generic Linux ACPI drivers.
16 This driver used to be named ibm-acpi until kernel 2.6.21 and release
17 0.13-20070314. It used to be in the drivers/acpi tree, but it was
18 moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel
19 2.6.22, and release 0.14.
25 The features currently supported are the following (see below for
26 detailed description):
29 - Bluetooth enable and disable
30 - video output switching, expansion control
31 - ThinkLight on and off
32 - limited docking and undocking
38 - Experimental: embedded controller register dump
39 - LCD brightness control
41 - Fan control and monitoring: fan speed, fan enable/disable
42 - Experimental: WAN enable and disable
44 A compatibility table by model and feature is maintained on the web
45 site, http://ibm-acpi.sf.net/. I appreciate any success or failure
46 reports, especially if they add to or correct the compatibility table.
47 Please include the following information in your report:
50 - a copy of your DSDT, from /proc/acpi/dsdt
51 - a copy of the output of dmidecode, with serial numbers
53 - which driver features work and which don't
54 - the observed behavior of non-working features
56 Any other comments or patches are also more than welcome.
62 If you are compiling this driver as included in the Linux kernel
63 sources, simply enable the CONFIG_THINKPAD_ACPI option, and optionally
64 enable the CONFIG_THINKPAD_ACPI_BAY option if you want the
65 thinkpad-specific bay functionality.
70 The driver exports two different interfaces to userspace, which can be
71 used to access the features it provides. One is a legacy procfs-based
72 interface, which will be removed at some time in the distant future.
73 The other is a new sysfs-based interface which is not complete yet.
75 The procfs interface creates the /proc/acpi/ibm directory. There is a
76 file under that directory for each feature it supports. The procfs
77 interface is mostly frozen, and will change very little if at all: it
78 will not be extended to add any new functionality in the driver, instead
79 all new functionality will be implemented on the sysfs interface.
81 The sysfs interface tries to blend in the generic Linux sysfs subsystems
82 and classes as much as possible. Since some of these subsystems are not
83 yet ready or stabilized, it is expected that this interface will change,
84 and any and all userspace programs must deal with it.
87 Notes about the sysfs interface:
89 Unlike what was done with the procfs interface, correctness when talking
90 to the sysfs interfaces will be enforced, as will correctness in the
91 thinkpad-acpi's implementation of sysfs interfaces.
93 Also, any bugs in the thinkpad-acpi sysfs driver code or in the
94 thinkpad-acpi's implementation of the sysfs interfaces will be fixed for
95 maximum correctness, even if that means changing an interface in
96 non-compatible ways. As these interfaces mature both in the kernel and
97 in thinkpad-acpi, such changes should become quite rare.
99 Applications interfacing to the thinkpad-acpi sysfs interfaces must
100 follow all sysfs guidelines and correctly process all errors (the sysfs
101 interface makes extensive use of errors). File descriptors and open /
102 close operations to the sysfs inodes must also be properly implemented.
104 The version of thinkpad-acpi's sysfs interface is exported by the driver
105 as a driver attribute (see below).
107 Sysfs driver attributes are on the driver's sysfs attribute space,
108 for 2.6.20 this is /sys/bus/platform/drivers/thinkpad-acpi/.
110 Sysfs device attributes are on the driver's sysfs attribute space,
111 for 2.6.20 this is /sys/devices/platform/thinkpad-acpi/.
116 procfs: /proc/acpi/ibm/driver
117 sysfs driver attribute: version
119 The driver name and version. No commands can be written to this file.
121 Sysfs interface version
122 -----------------------
124 sysfs driver attribute: interface_version
126 Version of the thinkpad-acpi sysfs interface, as an unsigned long
127 (output in hex format: 0xAAAABBCC), where:
128 AAAA - major revision
132 The sysfs interface version changelog for the driver can be found at the
133 end of this document. Changes to the sysfs interface done by the kernel
134 subsystems are not documented here, nor are they tracked by this
140 procfs: /proc/acpi/ibm/hotkey
141 sysfs device attribute: hotkey_*
143 Without this driver, only the Fn-F4 key (sleep button) generates an
144 ACPI event. With the driver loaded, the hotkey feature enabled and the
145 mask set (see below), the various hot keys generate ACPI events in the
148 ibm/hotkey HKEY 00000080 0000xxxx
150 The last four digits vary depending on the key combination pressed.
151 All labeled Fn-Fx key combinations generate distinct events. In
152 addition, the lid microswitch and some docking station buttons may
153 also generate such events.
155 The bit mask allows some control over which hot keys generate ACPI
156 events. Not all bits in the mask can be modified. Not all bits that
157 can be modified do anything. Not all hot keys can be individually
158 controlled by the mask. Most recent ThinkPad models honor the
159 following bits (assuming the hot keys feature has been enabled):
161 key bit behavior when set behavior when unset
163 Fn-F3 always generates ACPI event
164 Fn-F4 always generates ACPI event
165 Fn-F5 0010 generate ACPI event enable/disable Bluetooth
166 Fn-F7 0040 generate ACPI event switch LCD and external display
167 Fn-F8 0080 generate ACPI event expand screen or none
168 Fn-F9 0100 generate ACPI event none
169 Fn-F12 always generates ACPI event
171 Some models do not support all of the above. For example, the T30 does
172 not support Fn-F5 and Fn-F9. Other models do not support the mask at
173 all. On those models, hot keys cannot be controlled individually.
175 Note that enabling ACPI events for some keys prevents their default
176 behavior. For example, if events for Fn-F5 are enabled, that key will
177 no longer enable/disable Bluetooth by itself. This can still be done
178 from an acpid handler for the ibm/hotkey event.
180 Note also that not all Fn key combinations are supported through
181 ACPI. For example, on the X40, the brightness, volume and "Access IBM"
182 buttons do not generate ACPI events even with this driver. They *can*
183 be used through the "ThinkPad Buttons" utility, see
184 http://www.nongnu.org/tpb/
188 The following commands can be written to the /proc/acpi/ibm/hotkey file:
190 echo enable > /proc/acpi/ibm/hotkey -- enable the hot keys feature
191 echo disable > /proc/acpi/ibm/hotkey -- disable the hot keys feature
192 echo 0xffff > /proc/acpi/ibm/hotkey -- enable all possible hot keys
193 echo 0x0000 > /proc/acpi/ibm/hotkey -- disable all possible hot keys
194 ... any other 4-hex-digit mask ...
195 echo reset > /proc/acpi/ibm/hotkey -- restore the original mask
200 Returns the status of the hot keys feature when
201 thinkpad-acpi was loaded. Upon module unload, the hot
202 key feature status will be restored to this value.
204 0: hot keys were disabled
205 1: hot keys were enabled
208 Returns the hot keys mask when thinkpad-acpi was loaded.
209 Upon module unload, the hot keys mask will be restored
213 Enables/disables the hot keys feature, and reports
214 current status of the hot keys feature.
216 0: disables the hot keys feature / feature disabled
217 1: enables the hot keys feature / feature enabled
220 bit mask to enable ACPI event generation for each hot
221 key (see above). Returns the current status of the hot
222 keys mask, and allows one to modify it.
228 procfs: /proc/acpi/ibm/bluetooth
229 sysfs device attribute: bluetooth_enable
231 This feature shows the presence and current state of a ThinkPad
232 Bluetooth device in the internal ThinkPad CDC slot.
236 If Bluetooth is installed, the following commands can be used:
238 echo enable > /proc/acpi/ibm/bluetooth
239 echo disable > /proc/acpi/ibm/bluetooth
243 If the Bluetooth CDC card is installed, it can be enabled /
244 disabled through the "bluetooth_enable" thinkpad-acpi device
245 attribute, and its current status can also be queried.
248 0: disables Bluetooth / Bluetooth is disabled
249 1: enables Bluetooth / Bluetooth is enabled.
251 Note: this interface will be probably be superseeded by the
252 generic rfkill class, so it is NOT to be considered stable yet.
254 Video output control -- /proc/acpi/ibm/video
255 --------------------------------------------
257 This feature allows control over the devices used for video output -
258 LCD, CRT or DVI (if available). The following commands are available:
260 echo lcd_enable > /proc/acpi/ibm/video
261 echo lcd_disable > /proc/acpi/ibm/video
262 echo crt_enable > /proc/acpi/ibm/video
263 echo crt_disable > /proc/acpi/ibm/video
264 echo dvi_enable > /proc/acpi/ibm/video
265 echo dvi_disable > /proc/acpi/ibm/video
266 echo auto_enable > /proc/acpi/ibm/video
267 echo auto_disable > /proc/acpi/ibm/video
268 echo expand_toggle > /proc/acpi/ibm/video
269 echo video_switch > /proc/acpi/ibm/video
271 Each video output device can be enabled or disabled individually.
272 Reading /proc/acpi/ibm/video shows the status of each device.
274 Automatic video switching can be enabled or disabled. When automatic
275 video switching is enabled, certain events (e.g. opening the lid,
276 docking or undocking) cause the video output device to change
277 automatically. While this can be useful, it also causes flickering
278 and, on the X40, video corruption. By disabling automatic switching,
279 the flickering or video corruption can be avoided.
281 The video_switch command cycles through the available video outputs
282 (it simulates the behavior of Fn-F7).
284 Video expansion can be toggled through this feature. This controls
285 whether the display is expanded to fill the entire LCD screen when a
286 mode with less than full resolution is used. Note that the current
287 video expansion status cannot be determined through this feature.
289 Note that on many models (particularly those using Radeon graphics
290 chips) the X driver configures the video card in a way which prevents
291 Fn-F7 from working. This also disables the video output switching
292 features of this driver, as it uses the same ACPI methods as
293 Fn-F7. Video switching on the console should still work.
295 UPDATE: There's now a patch for the X.org Radeon driver which
296 addresses this issue. Some people are reporting success with the patch
297 while others are still having problems. For more information:
299 https://bugs.freedesktop.org/show_bug.cgi?id=2000
301 ThinkLight control -- /proc/acpi/ibm/light
302 ------------------------------------------
304 The current status of the ThinkLight can be found in this file. A few
305 models which do not make the status available will show it as
306 "unknown". The available commands are:
308 echo on > /proc/acpi/ibm/light
309 echo off > /proc/acpi/ibm/light
311 Docking / undocking -- /proc/acpi/ibm/dock
312 ------------------------------------------
314 Docking and undocking (e.g. with the X4 UltraBase) requires some
315 actions to be taken by the operating system to safely make or break
316 the electrical connections with the dock.
318 The docking feature of this driver generates the following ACPI events:
320 ibm/dock GDCK 00000003 00000001 -- eject request
321 ibm/dock GDCK 00000003 00000002 -- undocked
322 ibm/dock GDCK 00000000 00000003 -- docked
324 NOTE: These events will only be generated if the laptop was docked
325 when originally booted. This is due to the current lack of support for
326 hot plugging of devices in the Linux ACPI framework. If the laptop was
327 booted while not in the dock, the following message is shown in the
330 Mar 17 01:42:34 aero kernel: thinkpad_acpi: dock device not present
332 In this case, no dock-related events are generated but the dock and
333 undock commands described below still work. They can be executed
334 manually or triggered by Fn key combinations (see the example acpid
335 configuration files included in the driver tarball package available
338 When the eject request button on the dock is pressed, the first event
339 above is generated. The handler for this event should issue the
342 echo undock > /proc/acpi/ibm/dock
344 After the LED on the dock goes off, it is safe to eject the laptop.
345 Note: if you pressed this key by mistake, go ahead and eject the
346 laptop, then dock it back in. Otherwise, the dock may not function as
349 When the laptop is docked, the third event above is generated. The
350 handler for this event should issue the following command to fully
353 echo dock > /proc/acpi/ibm/dock
355 The contents of the /proc/acpi/ibm/dock file shows the current status
356 of the dock, as provided by the ACPI framework.
358 The docking support in this driver does not take care of enabling or
359 disabling any other devices you may have attached to the dock. For
360 example, a CD drive plugged into the UltraBase needs to be disabled or
361 enabled separately. See the provided example acpid configuration files
362 for how this can be accomplished.
364 There is no support yet for PCI devices that may be attached to a
365 docking station, e.g. in the ThinkPad Dock II. The driver currently
366 does not recognize, enable or disable such devices. This means that
367 the only docking stations currently supported are the X-series
368 UltraBase docks and "dumb" port replicators like the Mini Dock (the
369 latter don't need any ACPI support, actually).
371 UltraBay eject -- /proc/acpi/ibm/bay
372 ------------------------------------
374 Inserting or ejecting an UltraBay device requires some actions to be
375 taken by the operating system to safely make or break the electrical
376 connections with the device.
378 This feature generates the following ACPI events:
380 ibm/bay MSTR 00000003 00000000 -- eject request
381 ibm/bay MSTR 00000001 00000000 -- eject lever inserted
383 NOTE: These events will only be generated if the UltraBay was present
384 when the laptop was originally booted (on the X series, the UltraBay
385 is in the dock, so it may not be present if the laptop was undocked).
386 This is due to the current lack of support for hot plugging of devices
387 in the Linux ACPI framework. If the laptop was booted without the
388 UltraBay, the following message is shown in the logs:
390 Mar 17 01:42:34 aero kernel: thinkpad_acpi: bay device not present
392 In this case, no bay-related events are generated but the eject
393 command described below still works. It can be executed manually or
394 triggered by a hot key combination.
396 Sliding the eject lever generates the first event shown above. The
397 handler for this event should take whatever actions are necessary to
398 shut down the device in the UltraBay (e.g. call idectl), then issue
399 the following command:
401 echo eject > /proc/acpi/ibm/bay
403 After the LED on the UltraBay goes off, it is safe to pull out the
406 When the eject lever is inserted, the second event above is
407 generated. The handler for this event should take whatever actions are
408 necessary to enable the UltraBay device (e.g. call idectl).
410 The contents of the /proc/acpi/ibm/bay file shows the current status
411 of the UltraBay, as provided by the ACPI framework.
413 EXPERIMENTAL warm eject support on the 600e/x, A22p and A3x (To use
414 this feature, you need to supply the experimental=1 parameter when
417 These models do not have a button near the UltraBay device to request
418 a hot eject but rather require the laptop to be put to sleep
419 (suspend-to-ram) before the bay device is ejected or inserted).
420 The sequence of steps to eject the device is as follows:
422 echo eject > /proc/acpi/ibm/bay
423 put the ThinkPad to sleep
426 cat /proc/acpi/ibm/bay should show that the drive was removed
428 On the A3x, both the UltraBay 2000 and UltraBay Plus devices are
429 supported. Use "eject2" instead of "eject" for the second bay.
431 Note: the UltraBay eject support on the 600e/x, A22p and A3x is
432 EXPERIMENTAL and may not work as expected. USE WITH CAUTION!
437 procfs: /proc/acpi/ibm/cmos
438 sysfs device attribute: cmos_command
440 This feature is used internally by the ACPI firmware to control the
441 ThinkLight on most newer ThinkPad models. It may also control LCD
442 brightness, sounds volume and more, but only on some models.
444 The range of valid cmos command numbers is 0 to 21, but not all have an
445 effect and the behavior varies from model to model. Here is the behavior
446 on the X40 (tpb is the ThinkPad Buttons utility):
448 0 - no effect but tpb reports "Volume down"
449 1 - no effect but tpb reports "Volume up"
450 2 - no effect but tpb reports "Mute on"
451 3 - simulate pressing the "Access IBM" button
452 4 - LCD brightness up
453 5 - LCD brightness down
454 11 - toggle screen expansion
457 14 - no effect but tpb reports ThinkLight status change
459 The cmos command interface is prone to firmware split-brain problems, as
460 in newer ThinkPads it is just a compatibility layer.
462 LED control -- /proc/acpi/ibm/led
463 ---------------------------------
465 Some of the LED indicators can be controlled through this feature. The
466 available commands are:
468 echo '<led number> on' >/proc/acpi/ibm/led
469 echo '<led number> off' >/proc/acpi/ibm/led
470 echo '<led number> blink' >/proc/acpi/ibm/led
472 The <led number> range is 0 to 7. The set of LEDs that can be
473 controlled varies from model to model. Here is the mapping on the X40:
482 All of the above can be turned on and off and can be made to blink.
484 ACPI sounds -- /proc/acpi/ibm/beep
485 ----------------------------------
487 The BEEP method is used internally by the ACPI firmware to provide
488 audible alerts in various situations. This feature allows the same
489 sounds to be triggered manually.
491 The commands are non-negative integer numbers:
493 echo <number> >/proc/acpi/ibm/beep
495 The valid <number> range is 0 to 17. Not all numbers trigger sounds
496 and the sounds vary from model to model. Here is the behavior on the
499 0 - stop a sound in progress (but use 17 to stop 16)
500 2 - two beeps, pause, third beep ("low battery")
502 4 - high, followed by low-pitched beep ("unable")
504 6 - very high, followed by high-pitched beep ("AC/DC")
505 7 - high-pitched beep
506 9 - three short beeps
508 12 - low-pitched beep
509 15 - three high-pitched beeps repeating constantly, stop with 0
510 16 - one medium-pitched beep repeating constantly, stop with 17
516 procfs: /proc/acpi/ibm/thermal
517 sysfs device attributes: (hwmon) temp*_input
519 Most ThinkPads include six or more separate temperature sensors but
520 only expose the CPU temperature through the standard ACPI methods.
521 This feature shows readings from up to eight different sensors on older
522 ThinkPads, and it has experimental support for up to sixteen different
523 sensors on newer ThinkPads.
525 EXPERIMENTAL: The 16-sensors feature is marked EXPERIMENTAL because the
526 implementation directly accesses hardware registers and may not work as
527 expected. USE WITH CAUTION! To use this feature, you need to supply the
528 experimental=1 parameter when loading the module. When EXPERIMENTAL
529 mode is enabled, reading the first 8 sensors on newer ThinkPads will
530 also use an new experimental thermal sensor access mode.
532 For example, on the X40, a typical output may be:
533 temperatures: 42 42 45 41 36 -128 33 -128
535 EXPERIMENTAL: On the T43/p, a typical output may be:
536 temperatures: 48 48 36 52 38 -128 31 -128 48 52 48 -128 -128 -128 -128 -128
538 The mapping of thermal sensors to physical locations varies depending on
539 system-board model (and thus, on ThinkPad model).
541 http://thinkwiki.org/wiki/Thermal_Sensors is a public wiki page that
542 tries to track down these locations for various models.
544 Most (newer?) models seem to follow this pattern:
547 2: (depends on model)
548 3: (depends on model)
550 5: Main battery: main sensor
551 6: Bay battery: main sensor
552 7: Main battery: secondary sensor
553 8: Bay battery: secondary sensor
554 9-15: (depends on model)
556 For the R51 (source: Thomas Gruber):
560 For the T43, T43/p (source: Shmidoax/Thinkwiki.org)
561 http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_T43.2C_T43p
562 2: System board, left side (near PCMCIA slot), reported as HDAPS temp
564 9: MCH (northbridge) to DRAM Bus
565 10: Clock-generator, mini-pci card and ICH (southbridge), under Mini-PCI
567 11: Power regulator, underside of system board, below F2 key
569 The A31 has a very atypical layout for the thermal sensors
570 (source: Milos Popovic, http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_A31)
572 2: Main Battery: main sensor
574 4: Bay Battery: main sensor
577 7: Main Battery: secondary sensor
578 8: Bay Battery: secondary sensor
582 Readings from sensors that are not available return -128.
583 No commands can be written to this file.
586 Sensors that are not available return the ENXIO error. This
587 status may change at runtime, as there are hotplug thermal
588 sensors, like those inside the batteries and docks.
590 thinkpad-acpi thermal sensors are reported through the hwmon
591 subsystem, and follow all of the hwmon guidelines at
595 EXPERIMENTAL: Embedded controller register dump -- /proc/acpi/ibm/ecdump
596 ------------------------------------------------------------------------
598 This feature is marked EXPERIMENTAL because the implementation
599 directly accesses hardware registers and may not work as expected. USE
600 WITH CAUTION! To use this feature, you need to supply the
601 experimental=1 parameter when loading the module.
603 This feature dumps the values of 256 embedded controller
604 registers. Values which have changed since the last time the registers
605 were dumped are marked with a star:
607 [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump
608 EC +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f
609 EC 0x00: a7 47 87 01 fe 96 00 08 01 00 cb 00 00 00 40 00
610 EC 0x10: 00 00 ff ff f4 3c 87 09 01 ff 42 01 ff ff 0d 00
611 EC 0x20: 00 00 00 00 00 00 00 00 00 00 00 03 43 00 00 80
612 EC 0x30: 01 07 1a 00 30 04 00 00 *85 00 00 10 00 50 00 00
613 EC 0x40: 00 00 00 00 00 00 14 01 00 04 00 00 00 00 00 00
614 EC 0x50: 00 c0 02 0d 00 01 01 02 02 03 03 03 03 *bc *02 *bc
615 EC 0x60: *02 *bc *02 00 00 00 00 00 00 00 00 00 00 00 00 00
616 EC 0x70: 00 00 00 00 00 12 30 40 *24 *26 *2c *27 *20 80 *1f 80
617 EC 0x80: 00 00 00 06 *37 *0e 03 00 00 00 0e 07 00 00 00 00
618 EC 0x90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
619 EC 0xa0: *ff 09 ff 09 ff ff *64 00 *00 *00 *a2 41 *ff *ff *e0 00
620 EC 0xb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
621 EC 0xc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
622 EC 0xd0: 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
623 EC 0xe0: 00 00 00 00 00 00 00 00 11 20 49 04 24 06 55 03
624 EC 0xf0: 31 55 48 54 35 38 57 57 08 2f 45 73 07 65 6c 1a
626 This feature can be used to determine the register holding the fan
627 speed on some models. To do that, do the following:
629 - make sure the battery is fully charged
630 - make sure the fan is running
631 - run 'cat /proc/acpi/ibm/ecdump' several times, once per second or so
633 The first step makes sure various charging-related values don't
634 vary. The second ensures that the fan-related values do vary, since
635 the fan speed fluctuates a bit. The third will (hopefully) mark the
636 fan register with a star:
638 [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump
639 EC +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f
640 EC 0x00: a7 47 87 01 fe 96 00 08 01 00 cb 00 00 00 40 00
641 EC 0x10: 00 00 ff ff f4 3c 87 09 01 ff 42 01 ff ff 0d 00
642 EC 0x20: 00 00 00 00 00 00 00 00 00 00 00 03 43 00 00 80
643 EC 0x30: 01 07 1a 00 30 04 00 00 85 00 00 10 00 50 00 00
644 EC 0x40: 00 00 00 00 00 00 14 01 00 04 00 00 00 00 00 00
645 EC 0x50: 00 c0 02 0d 00 01 01 02 02 03 03 03 03 bc 02 bc
646 EC 0x60: 02 bc 02 00 00 00 00 00 00 00 00 00 00 00 00 00
647 EC 0x70: 00 00 00 00 00 12 30 40 24 27 2c 27 21 80 1f 80
648 EC 0x80: 00 00 00 06 *be 0d 03 00 00 00 0e 07 00 00 00 00
649 EC 0x90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
650 EC 0xa0: ff 09 ff 09 ff ff 64 00 00 00 a2 41 ff ff e0 00
651 EC 0xb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
652 EC 0xc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
653 EC 0xd0: 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
654 EC 0xe0: 00 00 00 00 00 00 00 00 11 20 49 04 24 06 55 03
655 EC 0xf0: 31 55 48 54 35 38 57 57 08 2f 45 73 07 65 6c 1a
657 Another set of values that varies often is the temperature
658 readings. Since temperatures don't change vary fast, you can take
659 several quick dumps to eliminate them.
661 You can use a similar method to figure out the meaning of other
662 embedded controller registers - e.g. make sure nothing else changes
663 except the charging or discharging battery to determine which
664 registers contain the current battery capacity, etc. If you experiment
665 with this, do send me your results (including some complete dumps with
666 a description of the conditions when they were taken.)
668 LCD brightness control
669 ----------------------
671 procfs: /proc/acpi/ibm/brightness
672 sysfs backlight device "thinkpad_screen"
674 This feature allows software control of the LCD brightness on ThinkPad
675 models which don't have a hardware brightness slider.
677 It has some limitations: the LCD backlight cannot be actually turned on or off
678 by this interface, and in many ThinkPad models, the "dim while on battery"
679 functionality will be enabled by the BIOS when this interface is used, and
680 cannot be controlled.
682 The backlight control has eight levels, ranging from 0 to 7. Some of the
683 levels may not be distinct.
687 The available commands are:
689 echo up >/proc/acpi/ibm/brightness
690 echo down >/proc/acpi/ibm/brightness
691 echo 'level <level>' >/proc/acpi/ibm/brightness
695 The interface is implemented through the backlight sysfs class, which is poorly
696 documented at this time.
698 Locate the thinkpad_screen device under /sys/class/backlight, and inside it
699 there will be the following attributes:
702 Reads the maximum brightness the hardware can be set to.
703 The minimum is always zero.
706 Reads what brightness the screen is set to at this instant.
709 Writes request the driver to change brightness to the given
710 value. Reads will tell you what brightness the driver is trying
711 to set the display to when "power" is set to zero and the display
712 has not been dimmed by a kernel power management event.
715 power management mode, where 0 is "display on", and 1 to 3 will
716 dim the display backlight to brightness level 0 because
717 thinkpad-acpi cannot really turn the backlight off. Kernel
718 power management events can temporarily increase the current
719 power management level, i.e. they can dim the display.
722 Volume control -- /proc/acpi/ibm/volume
723 ---------------------------------------
725 This feature allows volume control on ThinkPad models which don't have
726 a hardware volume knob. The available commands are:
728 echo up >/proc/acpi/ibm/volume
729 echo down >/proc/acpi/ibm/volume
730 echo mute >/proc/acpi/ibm/volume
731 echo 'level <level>' >/proc/acpi/ibm/volume
733 The <level> number range is 0 to 15 although not all of them may be
734 distinct. The unmute the volume after the mute command, use either the
735 up or down command (the level command will not unmute the volume).
736 The current volume level and mute state is shown in the file.
738 Fan control and monitoring: fan speed, fan enable/disable
739 ---------------------------------------------------------
741 procfs: /proc/acpi/ibm/fan
742 sysfs device attributes: (hwmon) fan_input, pwm1, pwm1_enable
744 NOTE NOTE NOTE: fan control operations are disabled by default for
745 safety reasons. To enable them, the module parameter "fan_control=1"
746 must be given to thinkpad-acpi.
748 This feature attempts to show the current fan speed, control mode and
749 other fan data that might be available. The speed is read directly
750 from the hardware registers of the embedded controller. This is known
751 to work on later R, T, X and Z series ThinkPads but may show a bogus
752 value on other models.
756 Most ThinkPad fans work in "levels" at the firmware interface. Level 0
757 stops the fan. The higher the level, the higher the fan speed, although
758 adjacent levels often map to the same fan speed. 7 is the highest
759 level, where the fan reaches the maximum recommended speed.
761 Level "auto" means the EC changes the fan level according to some
762 internal algorithm, usually based on readings from the thermal sensors.
764 There is also a "full-speed" level, also known as "disengaged" level.
765 In this level, the EC disables the speed-locked closed-loop fan control,
766 and drives the fan as fast as it can go, which might exceed hardware
767 limits, so use this level with caution.
769 The fan usually ramps up or down slowly from one speed to another, and
770 it is normal for the EC to take several seconds to react to fan
771 commands. The full-speed level may take up to two minutes to ramp up to
772 maximum speed, and in some ThinkPads, the tachometer readings go stale
773 while the EC is transitioning to the full-speed level.
775 WARNING WARNING WARNING: do not leave the fan disabled unless you are
776 monitoring all of the temperature sensor readings and you are ready to
777 enable it if necessary to avoid overheating.
779 An enabled fan in level "auto" may stop spinning if the EC decides the
780 ThinkPad is cool enough and doesn't need the extra airflow. This is
781 normal, and the EC will spin the fan up if the varios thermal readings
784 On the X40, this seems to depend on the CPU and HDD temperatures.
785 Specifically, the fan is turned on when either the CPU temperature
786 climbs to 56 degrees or the HDD temperature climbs to 46 degrees. The
787 fan is turned off when the CPU temperature drops to 49 degrees and the
788 HDD temperature drops to 41 degrees. These thresholds cannot
789 currently be controlled.
791 The ThinkPad's ACPI DSDT code will reprogram the fan on its own when
792 certain conditions are met. It will override any fan programming done
793 through thinkpad-acpi.
795 The thinkpad-acpi kernel driver can be programmed to revert the fan
796 level to a safe setting if userspace does not issue one of the procfs
797 fan commands: "enable", "disable", "level" or "watchdog", or if there
798 are no writes to pwm1_enable (or to pwm1 *if and only if* pwm1_enable is
799 set to 1, manual mode) within a configurable amount of time of up to
800 120 seconds. This functionality is called fan safety watchdog.
802 Note that the watchdog timer stops after it enables the fan. It will be
803 rearmed again automatically (using the same interval) when one of the
804 above mentioned fan commands is received. The fan watchdog is,
805 therefore, not suitable to protect against fan mode changes made through
806 means other than the "enable", "disable", and "level" procfs fan
807 commands, or the hwmon fan control sysfs interface.
811 The fan may be enabled or disabled with the following commands:
813 echo enable >/proc/acpi/ibm/fan
814 echo disable >/proc/acpi/ibm/fan
816 Placing a fan on level 0 is the same as disabling it. Enabling a fan
817 will try to place it in a safe level if it is too slow or disabled.
819 The fan level can be controlled with the command:
821 echo 'level <level>' > /proc/acpi/ibm/fan
823 Where <level> is an integer from 0 to 7, or one of the words "auto" or
824 "full-speed" (without the quotes). Not all ThinkPads support the "auto"
825 and "full-speed" levels. The driver accepts "disengaged" as an alias for
826 "full-speed", and reports it as "disengaged" for backwards
829 On the X31 and X40 (and ONLY on those models), the fan speed can be
830 controlled to a certain degree. Once the fan is running, it can be
831 forced to run faster or slower with the following command:
833 echo 'speed <speed>' > /proc/acpi/ibm/fan
835 The sustainable range of fan speeds on the X40 appears to be from about
836 3700 to about 7350. Values outside this range either do not have any
837 effect or the fan speed eventually settles somewhere in that range. The
838 fan cannot be stopped or started with this command. This functionality
839 is incomplete, and not available through the sysfs interface.
841 To program the safety watchdog, use the "watchdog" command.
843 echo 'watchdog <interval in seconds>' > /proc/acpi/ibm/fan
845 If you want to disable the watchdog, use 0 as the interval.
849 The sysfs interface follows the hwmon subsystem guidelines for the most
850 part, and the exception is the fan safety watchdog.
852 Writes to any of the sysfs attributes may return the EINVAL error if
853 that operation is not supported in a given ThinkPad or if the parameter
854 is out-of-bounds, and EPERM if it is forbidden. They may also return
855 EINTR (interrupted system call), and EIO (I/O error while trying to talk
858 Features not yet implemented by the driver return ENOSYS.
860 hwmon device attribute pwm1_enable:
861 0: PWM offline (fan is set to full-speed mode)
862 1: Manual PWM control (use pwm1 to set fan level)
863 2: Hardware PWM control (EC "auto" mode)
864 3: reserved (Software PWM control, not implemented yet)
866 Modes 0 and 2 are not supported by all ThinkPads, and the
867 driver is not always able to detect this. If it does know a
868 mode is unsupported, it will return -EINVAL.
870 hwmon device attribute pwm1:
871 Fan level, scaled from the firmware values of 0-7 to the hwmon
872 scale of 0-255. 0 means fan stopped, 255 means highest normal
875 This attribute only commands the fan if pmw1_enable is set to 1
876 (manual PWM control).
878 hwmon device attribute fan1_input:
879 Fan tachometer reading, in RPM. May go stale on certain
880 ThinkPads while the EC transitions the PWM to offline mode,
881 which can take up to two minutes. May return rubbish on older
884 driver attribute fan_watchdog:
885 Fan safety watchdog timer interval, in seconds. Minimum is
886 1 second, maximum is 120 seconds. 0 disables the watchdog.
888 To stop the fan: set pwm1 to zero, and pwm1_enable to 1.
890 To start the fan in a safe mode: set pwm1_enable to 2. If that fails
891 with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255
892 would be the safest choice, though).
898 procfs: /proc/acpi/ibm/wan
899 sysfs device attribute: wwan_enable
901 This feature is marked EXPERIMENTAL because the implementation
902 directly accesses hardware registers and may not work as expected. USE
903 WITH CAUTION! To use this feature, you need to supply the
904 experimental=1 parameter when loading the module.
906 This feature shows the presence and current state of a W-WAN (Sierra
907 Wireless EV-DO) device.
909 It was tested on a Lenovo Thinkpad X60. It should probably work on other
910 Thinkpad models which come with this module installed.
914 If the W-WAN card is installed, the following commands can be used:
916 echo enable > /proc/acpi/ibm/wan
917 echo disable > /proc/acpi/ibm/wan
921 If the W-WAN card is installed, it can be enabled /
922 disabled through the "wwan_enable" thinkpad-acpi device
923 attribute, and its current status can also be queried.
926 0: disables WWAN card / WWAN card is disabled
927 1: enables WWAN card / WWAN card is enabled.
929 Note: this interface will be probably be superseeded by the
930 generic rfkill class, so it is NOT to be considered stable yet.
932 Multiple Commands, Module Parameters
933 ------------------------------------
935 Multiple commands can be written to the proc files in one shot by
936 separating them with commas, for example:
938 echo enable,0xffff > /proc/acpi/ibm/hotkey
939 echo lcd_disable,crt_enable > /proc/acpi/ibm/video
941 Commands can also be specified when loading the thinkpad-acpi module,
944 modprobe thinkpad_acpi hotkey=enable,0xffff video=auto_disable
946 Enabling debugging output
947 -------------------------
949 The module takes a debug paramater which can be used to selectively
950 enable various classes of debugging output, for example:
952 modprobe ibm_acpi debug=0xffff
954 will enable all debugging output classes. It takes a bitmask, so
955 to enable more than one output class, just add their values.
957 Debug bitmask Description
958 0x0001 Initialization and probing
961 There is also a kernel build option to enable more debugging
962 information, which may be necessary to debug driver problems.
964 The level of debugging information output by the driver can be changed
965 at runtime through sysfs, using the driver attribute debug_level. The
966 attribute takes the same bitmask as the debug module parameter above.
968 Force loading of module
969 -----------------------
971 If thinkpad-acpi refuses to detect your ThinkPad, you can try to specify
972 the module parameter force_load=1. Regardless of whether this works or
973 not, please contact ibm-acpi-devel@lists.sourceforge.net with a report.
976 Sysfs interface changelog:
978 0x000100: Initial sysfs support, as a single platform driver and