Documentation/thinkpad-acpi.txt

   1                      ThinkPad ACPI Extras Driver
   2
   3                             Version 0.14
   4                           April 21st, 2007
   5
   6                Borislav Deianov <borislav@users.sf.net>
   7              Henrique de Moraes Holschuh <hmh@hmh.eng.br>
   8                       http://ibm-acpi.sf.net/
   9
  10
  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.
  15
  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.
  20
  21
  22 Status
  23 ------
  24
  25 The features currently supported are the following (see below for
  26 detailed description):
  27
  28         - Fn key combinations
  29         - Bluetooth enable and disable
  30         - video output switching, expansion control
  31         - ThinkLight on and off
  32         - limited docking and undocking
  33         - UltraBay eject
  34         - CMOS control
  35         - LED control
  36         - ACPI sounds
  37         - temperature sensors
  38         - Experimental: embedded controller register dump
  39         - LCD brightness control
  40         - Volume control
  41         - Fan control and monitoring: fan speed, fan enable/disable
  42         - Experimental: WAN enable and disable
  43
  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:
  48
  49         - ThinkPad model name
  50         - a copy of your DSDT, from /proc/acpi/dsdt
  51         - a copy of the output of dmidecode, with serial numbers
  52           and UUIDs masked off
  53         - which driver features work and which don't
  54         - the observed behavior of non-working features
  55
  56 Any other comments or patches are also more than welcome.
  57
  58
  59 Installation
  60 ------------
  61
  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.
  66
  67 Features
  68 --------
  69
  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.
  74
  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.
  80
  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.
  85
  86
  87 Notes about the sysfs interface:
  88
  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.
  92
  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.
  98
  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.
 103
 104 The version of thinkpad-acpi's sysfs interface is exported by the driver
 105 as a driver attribute (see below).
 106
 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/.
 109
 110 Sysfs device attributes are on the driver's sysfs attribute space,
 111 for 2.6.20 this is /sys/devices/platform/thinkpad-acpi/.
 112
 113 Driver version
 114 --------------
 115
 116 procfs: /proc/acpi/ibm/driver
 117 sysfs driver attribute: version
 118
 119 The driver name and version. No commands can be written to this file.
 120
 121 Sysfs interface version
 122 -----------------------
 123
 124 sysfs driver attribute: interface_version
 125
 126 Version of the thinkpad-acpi sysfs interface, as an unsigned long
 127 (output in hex format: 0xAAAABBCC), where:
 128         AAAA - major revision
 129         BB - minor revision
 130         CC - bugfix revision
 131
 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
 135 attribute.
 136
 137 Hot keys
 138 --------
 139
 140 procfs: /proc/acpi/ibm/hotkey
 141 sysfs device attribute: hotkey/*
 142
 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
 146 following format:
 147
 148         ibm/hotkey HKEY 00000080 0000xxxx
 149
 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.
 154
 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):
 160
 161         key     bit     behavior when set       behavior when unset
 162
 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
 170
 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.
 174
 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.
 179
 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/
 185
 186 procfs notes:
 187
 188 The following commands can be written to the /proc/acpi/ibm/hotkey file:
 189
 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
 196
 197 sysfs notes:
 198
 199         The hot keys attributes are in a hotkey/ subdirectory off the
 200         thinkpad device.
 201
 202         bios_enabled:
 203                 Returns the status of the hot keys feature when
 204                 thinkpad-acpi was loaded.  Upon module unload, the hot
 205                 key feature status will be restored to this value.
 206
 207                 0: hot keys were disabled
 208                 1: hot keys were enabled
 209
 210         bios_mask:
 211                 Returns the hot keys mask when thinkpad-acpi was loaded.
 212                 Upon module unload, the hot keys mask will be restored
 213                 to this value.
 214
 215         enable:
 216                 Enables/disables the hot keys feature, and reports
 217                 current status of the hot keys feature.
 218
 219                 0: disables the hot keys feature / feature disabled
 220                 1: enables the hot keys feature / feature enabled
 221
 222         mask:
 223                 bit mask to enable ACPI event generation for each hot
 224                 key (see above).  Returns the current status of the hot
 225                 keys mask, and allows one to modify it.
 226
 227
 228 Bluetooth
 229 ---------
 230
 231 procfs: /proc/acpi/ibm/bluetooth
 232 sysfs device attribute: bluetooth/enable
 233
 234 This feature shows the presence and current state of a ThinkPad
 235 Bluetooth device in the internal ThinkPad CDC slot.
 236
 237 Procfs notes:
 238
 239 If Bluetooth is installed, the following commands can be used:
 240
 241         echo enable > /proc/acpi/ibm/bluetooth
 242         echo disable > /proc/acpi/ibm/bluetooth
 243
 244 Sysfs notes:
 245
 246         If the Bluetooth CDC card is installed, it can be enabled /
 247         disabled through the "bluetooth/enable" thinkpad-acpi device
 248         attribute, and its current status can also be queried.
 249
 250         enable:
 251                 0: disables Bluetooth / Bluetooth is disabled
 252                 1: enables Bluetooth / Bluetooth is enabled.
 253
 254         Note: this interface will be probably be superseeded by the
 255         generic rfkill class.
 256
 257 Video output control -- /proc/acpi/ibm/video
 258 --------------------------------------------
 259
 260 This feature allows control over the devices used for video output -
 261 LCD, CRT or DVI (if available). The following commands are available:
 262
 263         echo lcd_enable > /proc/acpi/ibm/video
 264         echo lcd_disable > /proc/acpi/ibm/video
 265         echo crt_enable > /proc/acpi/ibm/video
 266         echo crt_disable > /proc/acpi/ibm/video
 267         echo dvi_enable > /proc/acpi/ibm/video
 268         echo dvi_disable > /proc/acpi/ibm/video
 269         echo auto_enable > /proc/acpi/ibm/video
 270         echo auto_disable > /proc/acpi/ibm/video
 271         echo expand_toggle > /proc/acpi/ibm/video
 272         echo video_switch > /proc/acpi/ibm/video
 273
 274 Each video output device can be enabled or disabled individually.
 275 Reading /proc/acpi/ibm/video shows the status of each device.
 276
 277 Automatic video switching can be enabled or disabled.  When automatic
 278 video switching is enabled, certain events (e.g. opening the lid,
 279 docking or undocking) cause the video output device to change
 280 automatically. While this can be useful, it also causes flickering
 281 and, on the X40, video corruption. By disabling automatic switching,
 282 the flickering or video corruption can be avoided.
 283
 284 The video_switch command cycles through the available video outputs
 285 (it simulates the behavior of Fn-F7).
 286
 287 Video expansion can be toggled through this feature. This controls
 288 whether the display is expanded to fill the entire LCD screen when a
 289 mode with less than full resolution is used. Note that the current
 290 video expansion status cannot be determined through this feature.
 291
 292 Note that on many models (particularly those using Radeon graphics
 293 chips) the X driver configures the video card in a way which prevents
 294 Fn-F7 from working. This also disables the video output switching
 295 features of this driver, as it uses the same ACPI methods as
 296 Fn-F7. Video switching on the console should still work.
 297
 298 UPDATE: There's now a patch for the X.org Radeon driver which
 299 addresses this issue. Some people are reporting success with the patch
 300 while others are still having problems. For more information:
 301
 302 https://bugs.freedesktop.org/show_bug.cgi?id=2000
 303
 304 ThinkLight control -- /proc/acpi/ibm/light
 305 ------------------------------------------
 306
 307 The current status of the ThinkLight can be found in this file. A few
 308 models which do not make the status available will show it as
 309 "unknown". The available commands are:
 310
 311         echo on  > /proc/acpi/ibm/light
 312         echo off > /proc/acpi/ibm/light
 313
 314 Docking / undocking -- /proc/acpi/ibm/dock
 315 ------------------------------------------
 316
 317 Docking and undocking (e.g. with the X4 UltraBase) requires some
 318 actions to be taken by the operating system to safely make or break
 319 the electrical connections with the dock.
 320
 321 The docking feature of this driver generates the following ACPI events:
 322
 323         ibm/dock GDCK 00000003 00000001 -- eject request
 324         ibm/dock GDCK 00000003 00000002 -- undocked
 325         ibm/dock GDCK 00000000 00000003 -- docked
 326
 327 NOTE: These events will only be generated if the laptop was docked
 328 when originally booted. This is due to the current lack of support for
 329 hot plugging of devices in the Linux ACPI framework. If the laptop was
 330 booted while not in the dock, the following message is shown in the
 331 logs:
 332
 333         Mar 17 01:42:34 aero kernel: thinkpad_acpi: dock device not present
 334
 335 In this case, no dock-related events are generated but the dock and
 336 undock commands described below still work. They can be executed
 337 manually or triggered by Fn key combinations (see the example acpid
 338 configuration files included in the driver tarball package available
 339 on the web site).
 340
 341 When the eject request button on the dock is pressed, the first event
 342 above is generated. The handler for this event should issue the
 343 following command:
 344
 345         echo undock > /proc/acpi/ibm/dock
 346
 347 After the LED on the dock goes off, it is safe to eject the laptop.
 348 Note: if you pressed this key by mistake, go ahead and eject the
 349 laptop, then dock it back in. Otherwise, the dock may not function as
 350 expected.
 351
 352 When the laptop is docked, the third event above is generated. The
 353 handler for this event should issue the following command to fully
 354 enable the dock:
 355
 356         echo dock > /proc/acpi/ibm/dock
 357
 358 The contents of the /proc/acpi/ibm/dock file shows the current status
 359 of the dock, as provided by the ACPI framework.
 360
 361 The docking support in this driver does not take care of enabling or
 362 disabling any other devices you may have attached to the dock. For
 363 example, a CD drive plugged into the UltraBase needs to be disabled or
 364 enabled separately. See the provided example acpid configuration files
 365 for how this can be accomplished.
 366
 367 There is no support yet for PCI devices that may be attached to a
 368 docking station, e.g. in the ThinkPad Dock II. The driver currently
 369 does not recognize, enable or disable such devices. This means that
 370 the only docking stations currently supported are the X-series
 371 UltraBase docks and "dumb" port replicators like the Mini Dock (the
 372 latter don't need any ACPI support, actually).
 373
 374 UltraBay eject -- /proc/acpi/ibm/bay
 375 ------------------------------------
 376
 377 Inserting or ejecting an UltraBay device requires some actions to be
 378 taken by the operating system to safely make or break the electrical
 379 connections with the device.
 380
 381 This feature generates the following ACPI events:
 382
 383         ibm/bay MSTR 00000003 00000000 -- eject request
 384         ibm/bay MSTR 00000001 00000000 -- eject lever inserted
 385
 386 NOTE: These events will only be generated if the UltraBay was present
 387 when the laptop was originally booted (on the X series, the UltraBay
 388 is in the dock, so it may not be present if the laptop was undocked).
 389 This is due to the current lack of support for hot plugging of devices
 390 in the Linux ACPI framework. If the laptop was booted without the
 391 UltraBay, the following message is shown in the logs:
 392
 393         Mar 17 01:42:34 aero kernel: thinkpad_acpi: bay device not present
 394
 395 In this case, no bay-related events are generated but the eject
 396 command described below still works. It can be executed manually or
 397 triggered by a hot key combination.
 398
 399 Sliding the eject lever generates the first event shown above. The
 400 handler for this event should take whatever actions are necessary to
 401 shut down the device in the UltraBay (e.g. call idectl), then issue
 402 the following command:
 403
 404         echo eject > /proc/acpi/ibm/bay
 405
 406 After the LED on the UltraBay goes off, it is safe to pull out the
 407 device.
 408
 409 When the eject lever is inserted, the second event above is
 410 generated. The handler for this event should take whatever actions are
 411 necessary to enable the UltraBay device (e.g. call idectl).
 412
 413 The contents of the /proc/acpi/ibm/bay file shows the current status
 414 of the UltraBay, as provided by the ACPI framework.
 415
 416 EXPERIMENTAL warm eject support on the 600e/x, A22p and A3x (To use
 417 this feature, you need to supply the experimental=1 parameter when
 418 loading the module):
 419
 420 These models do not have a button near the UltraBay device to request
 421 a hot eject but rather require the laptop to be put to sleep
 422 (suspend-to-ram) before the bay device is ejected or inserted).
 423 The sequence of steps to eject the device is as follows:
 424
 425         echo eject > /proc/acpi/ibm/bay
 426         put the ThinkPad to sleep
 427         remove the drive
 428         resume from sleep
 429         cat /proc/acpi/ibm/bay should show that the drive was removed
 430
 431 On the A3x, both the UltraBay 2000 and UltraBay Plus devices are
 432 supported. Use "eject2" instead of "eject" for the second bay.
 433
 434 Note: the UltraBay eject support on the 600e/x, A22p and A3x is
 435 EXPERIMENTAL and may not work as expected. USE WITH CAUTION!
 436
 437 CMOS control
 438 ------------
 439
 440 procfs: /proc/acpi/ibm/cmos
 441 sysfs device attribute: cmos_command
 442
 443 This feature is used internally by the ACPI firmware to control the
 444 ThinkLight on most newer ThinkPad models. It may also control LCD
 445 brightness, sounds volume and more, but only on some models.
 446
 447 The range of valid cmos command numbers is 0 to 21, but not all have an
 448 effect and the behavior varies from model to model.  Here is the behavior
 449 on the X40 (tpb is the ThinkPad Buttons utility):
 450
 451         0 - no effect but tpb reports "Volume down"
 452         1 - no effect but tpb reports "Volume up"
 453         2 - no effect but tpb reports "Mute on"
 454         3 - simulate pressing the "Access IBM" button
 455         4 - LCD brightness up
 456         5 - LCD brightness down
 457         11 - toggle screen expansion
 458         12 - ThinkLight on
 459         13 - ThinkLight off
 460         14 - no effect but tpb reports ThinkLight status change
 461
 462 The cmos command interface is prone to firmware split-brain problems, as
 463 in newer ThinkPads it is just a compatibility layer.
 464
 465 LED control -- /proc/acpi/ibm/led
 466 ---------------------------------
 467
 468 Some of the LED indicators can be controlled through this feature. The
 469 available commands are:
 470
 471         echo '<led number> on' >/proc/acpi/ibm/led
 472         echo '<led number> off' >/proc/acpi/ibm/led
 473         echo '<led number> blink' >/proc/acpi/ibm/led
 474
 475 The <led number> range is 0 to 7. The set of LEDs that can be
 476 controlled varies from model to model. Here is the mapping on the X40:
 477
 478         0 - power
 479         1 - battery (orange)
 480         2 - battery (green)
 481         3 - UltraBase
 482         4 - UltraBay
 483         7 - standby
 484
 485 All of the above can be turned on and off and can be made to blink.
 486
 487 ACPI sounds -- /proc/acpi/ibm/beep
 488 ----------------------------------
 489
 490 The BEEP method is used internally by the ACPI firmware to provide
 491 audible alerts in various situations. This feature allows the same
 492 sounds to be triggered manually.
 493
 494 The commands are non-negative integer numbers:
 495
 496         echo <number> >/proc/acpi/ibm/beep
 497
 498 The valid <number> range is 0 to 17. Not all numbers trigger sounds
 499 and the sounds vary from model to model. Here is the behavior on the
 500 X40:
 501
 502         0 - stop a sound in progress (but use 17 to stop 16)
 503         2 - two beeps, pause, third beep ("low battery")
 504         3 - single beep
 505         4 - high, followed by low-pitched beep ("unable")
 506         5 - single beep
 507         6 - very high, followed by high-pitched beep ("AC/DC")
 508         7 - high-pitched beep
 509         9 - three short beeps
 510         10 - very long beep
 511         12 - low-pitched beep
 512         15 - three high-pitched beeps repeating constantly, stop with 0
 513         16 - one medium-pitched beep repeating constantly, stop with 17
 514         17 - stop 16
 515
 516 Temperature sensors
 517 -------------------
 518
 519 procfs: /proc/acpi/ibm/thermal
 520 sysfs device attributes: (hwmon) temp*_input
 521
 522 Most ThinkPads include six or more separate temperature sensors but
 523 only expose the CPU temperature through the standard ACPI methods.
 524 This feature shows readings from up to eight different sensors on older
 525 ThinkPads, and it has experimental support for up to sixteen different
 526 sensors on newer ThinkPads.
 527
 528 EXPERIMENTAL: The 16-sensors feature is marked EXPERIMENTAL because the
 529 implementation directly accesses hardware registers and may not work as
 530 expected. USE WITH CAUTION! To use this feature, you need to supply the
 531 experimental=1 parameter when loading the module.  When EXPERIMENTAL
 532 mode is enabled, reading the first 8 sensors on newer ThinkPads will
 533 also use an new experimental thermal sensor access mode.
 534
 535 For example, on the X40, a typical output may be:
 536 temperatures:   42 42 45 41 36 -128 33 -128
 537
 538 EXPERIMENTAL: On the T43/p, a typical output may be:
 539 temperatures:   48 48 36 52 38 -128 31 -128 48 52 48 -128 -128 -128 -128 -128
 540
 541 The mapping of thermal sensors to physical locations varies depending on
 542 system-board model (and thus, on ThinkPad model).
 543
 544 http://thinkwiki.org/wiki/Thermal_Sensors is a public wiki page that
 545 tries to track down these locations for various models.
 546
 547 Most (newer?) models seem to follow this pattern:
 548
 549 1:  CPU
 550 2:  (depends on model)
 551 3:  (depends on model)
 552 4:  GPU
 553 5:  Main battery: main sensor
 554 6:  Bay battery: main sensor
 555 7:  Main battery: secondary sensor
 556 8:  Bay battery: secondary sensor
 557 9-15: (depends on model)
 558
 559 For the R51 (source: Thomas Gruber):
 560 2:  Mini-PCI
 561 3:  Internal HDD
 562
 563 For the T43, T43/p (source: Shmidoax/Thinkwiki.org)
 564 http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_T43.2C_T43p
 565 2:  System board, left side (near PCMCIA slot), reported as HDAPS temp
 566 3:  PCMCIA slot
 567 9:  MCH (northbridge) to DRAM Bus
 568 10: ICH (southbridge), under Mini-PCI card, under touchpad
 569 11: Power regulator, underside of system board, below F2 key
 570
 571 The A31 has a very atypical layout for the thermal sensors
 572 (source: Milos Popovic, http://thinkwiki.org/wiki/Thermal_Sensors#ThinkPad_A31)
 573 1:  CPU
 574 2:  Main Battery: main sensor
 575 3:  Power Converter
 576 4:  Bay Battery: main sensor
 577 5:  MCH (northbridge)
 578 6:  PCMCIA/ambient
 579 7:  Main Battery: secondary sensor
 580 8:  Bay Battery: secondary sensor
 581
 582
 583 Procfs notes:
 584         Readings from sensors that are not available return -128.
 585         No commands can be written to this file.
 586
 587 Sysfs notes:
 588         Sensors that are not available return the ENXIO error.  This
 589         status may change at runtime, as there are hotplug thermal
 590         sensors, like those inside the batteries and docks.
 591
 592         thinkpad-acpi thermal sensors are reported through the hwmon
 593         subsystem, and follow all of the hwmon guidelines at
 594         Documentation/hwmon.
 595
 596
 597 EXPERIMENTAL: Embedded controller register dump -- /proc/acpi/ibm/ecdump
 598 ------------------------------------------------------------------------
 599
 600 This feature is marked EXPERIMENTAL because the implementation
 601 directly accesses hardware registers and may not work as expected. USE
 602 WITH CAUTION! To use this feature, you need to supply the
 603 experimental=1 parameter when loading the module.
 604
 605 This feature dumps the values of 256 embedded controller
 606 registers. Values which have changed since the last time the registers
 607 were dumped are marked with a star:
 608
 609 [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump
 610 EC       +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f
 611 EC 0x00:  a7  47  87  01  fe  96  00  08  01  00  cb  00  00  00  40  00
 612 EC 0x10:  00  00  ff  ff  f4  3c  87  09  01  ff  42  01  ff  ff  0d  00
 613 EC 0x20:  00  00  00  00  00  00  00  00  00  00  00  03  43  00  00  80
 614 EC 0x30:  01  07  1a  00  30  04  00  00 *85  00  00  10  00  50  00  00
 615 EC 0x40:  00  00  00  00  00  00  14  01  00  04  00  00  00  00  00  00
 616 EC 0x50:  00  c0  02  0d  00  01  01  02  02  03  03  03  03 *bc *02 *bc
 617 EC 0x60: *02 *bc *02  00  00  00  00  00  00  00  00  00  00  00  00  00
 618 EC 0x70:  00  00  00  00  00  12  30  40 *24 *26 *2c *27 *20  80 *1f  80
 619 EC 0x80:  00  00  00  06 *37 *0e  03  00  00  00  0e  07  00  00  00  00
 620 EC 0x90:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 621 EC 0xa0: *ff  09  ff  09  ff  ff *64  00 *00 *00 *a2  41 *ff *ff *e0  00
 622 EC 0xb0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 623 EC 0xc0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 624 EC 0xd0:  03  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 625 EC 0xe0:  00  00  00  00  00  00  00  00  11  20  49  04  24  06  55  03
 626 EC 0xf0:  31  55  48  54  35  38  57  57  08  2f  45  73  07  65  6c  1a
 627
 628 This feature can be used to determine the register holding the fan
 629 speed on some models. To do that, do the following:
 630
 631         - make sure the battery is fully charged
 632         - make sure the fan is running
 633         - run 'cat /proc/acpi/ibm/ecdump' several times, once per second or so
 634
 635 The first step makes sure various charging-related values don't
 636 vary. The second ensures that the fan-related values do vary, since
 637 the fan speed fluctuates a bit. The third will (hopefully) mark the
 638 fan register with a star:
 639
 640 [root@x40 ibm-acpi]# cat /proc/acpi/ibm/ecdump
 641 EC       +00 +01 +02 +03 +04 +05 +06 +07 +08 +09 +0a +0b +0c +0d +0e +0f
 642 EC 0x00:  a7  47  87  01  fe  96  00  08  01  00  cb  00  00  00  40  00
 643 EC 0x10:  00  00  ff  ff  f4  3c  87  09  01  ff  42  01  ff  ff  0d  00
 644 EC 0x20:  00  00  00  00  00  00  00  00  00  00  00  03  43  00  00  80
 645 EC 0x30:  01  07  1a  00  30  04  00  00  85  00  00  10  00  50  00  00
 646 EC 0x40:  00  00  00  00  00  00  14  01  00  04  00  00  00  00  00  00
 647 EC 0x50:  00  c0  02  0d  00  01  01  02  02  03  03  03  03  bc  02  bc
 648 EC 0x60:  02  bc  02  00  00  00  00  00  00  00  00  00  00  00  00  00
 649 EC 0x70:  00  00  00  00  00  12  30  40  24  27  2c  27  21  80  1f  80
 650 EC 0x80:  00  00  00  06 *be  0d  03  00  00  00  0e  07  00  00  00  00
 651 EC 0x90:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 652 EC 0xa0:  ff  09  ff  09  ff  ff  64  00  00  00  a2  41  ff  ff  e0  00
 653 EC 0xb0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 654 EC 0xc0:  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 655 EC 0xd0:  03  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00
 656 EC 0xe0:  00  00  00  00  00  00  00  00  11  20  49  04  24  06  55  03
 657 EC 0xf0:  31  55  48  54  35  38  57  57  08  2f  45  73  07  65  6c  1a
 658
 659 Another set of values that varies often is the temperature
 660 readings. Since temperatures don't change vary fast, you can take
 661 several quick dumps to eliminate them.
 662
 663 You can use a similar method to figure out the meaning of other
 664 embedded controller registers - e.g. make sure nothing else changes
 665 except the charging or discharging battery to determine which
 666 registers contain the current battery capacity, etc. If you experiment
 667 with this, do send me your results (including some complete dumps with
 668 a description of the conditions when they were taken.)
 669
 670 LCD brightness control
 671 ----------------------
 672
 673 procfs: /proc/acpi/ibm/brightness
 674 sysfs backlight device "thinkpad_screen"
 675
 676 This feature allows software control of the LCD brightness on ThinkPad
 677 models which don't have a hardware brightness slider.
 678
 679 It has some limitations: the LCD backlight cannot be actually turned on or off
 680 by this interface, and in many ThinkPad models, the "dim while on battery"
 681 functionality will be enabled by the BIOS when this interface is used, and
 682 cannot be controlled.
 683
 684 The backlight control has eight levels, ranging from 0 to 7.  Some of the
 685 levels may not be distinct.
 686
 687 Procfs notes:
 688
 689         The available commands are:
 690
 691         echo up   >/proc/acpi/ibm/brightness
 692         echo down >/proc/acpi/ibm/brightness
 693         echo 'level <level>' >/proc/acpi/ibm/brightness
 694
 695 Sysfs notes:
 696
 697 The interface is implemented through the backlight sysfs class, which is poorly
 698 documented at this time.
 699
 700 Locate the thinkpad_screen device under /sys/class/backlight, and inside it
 701 there will be the following attributes:
 702
 703         max_brightness:
 704                 Reads the maximum brightness the hardware can be set to.
 705                 The minimum is always zero.
 706
 707         actual_brightness:
 708                 Reads what brightness the screen is set to at this instant.
 709
 710         brightness:
 711                 Writes request the driver to change brightness to the given
 712                 value.  Reads will tell you what brightness the driver is trying
 713                 to set the display to when "power" is set to zero and the display
 714                 has not been dimmed by a kernel power management event.
 715
 716         power:
 717                 power management mode, where 0 is "display on", and 1 to 3 will
 718                 dim the display backlight to brightness level 0 because
 719                 thinkpad-acpi cannot really turn the backlight off.  Kernel
 720                 power management events can temporarily increase the current
 721                 power management level, i.e. they can dim the display.
 722
 723
 724 Volume control -- /proc/acpi/ibm/volume
 725 ---------------------------------------
 726
 727 This feature allows volume control on ThinkPad models which don't have
 728 a hardware volume knob. The available commands are:
 729
 730         echo up   >/proc/acpi/ibm/volume
 731         echo down >/proc/acpi/ibm/volume
 732         echo mute >/proc/acpi/ibm/volume
 733         echo 'level <level>' >/proc/acpi/ibm/volume
 734
 735 The <level> number range is 0 to 15 although not all of them may be
 736 distinct. The unmute the volume after the mute command, use either the
 737 up or down command (the level command will not unmute the volume).
 738 The current volume level and mute state is shown in the file.
 739
 740 Fan control and monitoring: fan speed, fan enable/disable
 741 ---------------------------------------------------------
 742
 743 procfs: /proc/acpi/ibm/fan
 744 sysfs device attributes: (hwmon) fan_input, pwm1, pwm1_enable
 745
 746 NOTE NOTE NOTE: fan control operations are disabled by default for
 747 safety reasons.  To enable them, the module parameter "fan_control=1"
 748 must be given to thinkpad-acpi.
 749
 750 This feature attempts to show the current fan speed, control mode and
 751 other fan data that might be available.  The speed is read directly
 752 from the hardware registers of the embedded controller.  This is known
 753 to work on later R, T, X and Z series ThinkPads but may show a bogus
 754 value on other models.
 755
 756 Fan levels:
 757
 758 Most ThinkPad fans work in "levels" at the firmware interface.  Level 0
 759 stops the fan.  The higher the level, the higher the fan speed, although
 760 adjacent levels often map to the same fan speed.  7 is the highest
 761 level, where the fan reaches the maximum recommended speed.
 762
 763 Level "auto" means the EC changes the fan level according to some
 764 internal algorithm, usually based on readings from the thermal sensors.
 765
 766 There is also a "full-speed" level, also known as "disengaged" level.
 767 In this level, the EC disables the speed-locked closed-loop fan control,
 768 and drives the fan as fast as it can go, which might exceed hardware
 769 limits, so use this level with caution.
 770
 771 The fan usually ramps up or down slowly from one speed to another, and
 772 it is normal for the EC to take several seconds to react to fan
 773 commands.  The full-speed level may take up to two minutes to ramp up to
 774 maximum speed, and in some ThinkPads, the tachometer readings go stale
 775 while the EC is transitioning to the full-speed level.
 776
 777 WARNING WARNING WARNING: do not leave the fan disabled unless you are
 778 monitoring all of the temperature sensor readings and you are ready to
 779 enable it if necessary to avoid overheating.
 780
 781 An enabled fan in level "auto" may stop spinning if the EC decides the
 782 ThinkPad is cool enough and doesn't need the extra airflow.  This is
 783 normal, and the EC will spin the fan up if the varios thermal readings
 784 rise too much.
 785
 786 On the X40, this seems to depend on the CPU and HDD temperatures.
 787 Specifically, the fan is turned on when either the CPU temperature
 788 climbs to 56 degrees or the HDD temperature climbs to 46 degrees.  The
 789 fan is turned off when the CPU temperature drops to 49 degrees and the
 790 HDD temperature drops to 41 degrees.  These thresholds cannot
 791 currently be controlled.
 792
 793 The ThinkPad's ACPI DSDT code will reprogram the fan on its own when
 794 certain conditions are met.  It will override any fan programming done
 795 through thinkpad-acpi.
 796
 797 The thinkpad-acpi kernel driver can be programmed to revert the fan
 798 level to a safe setting if userspace does not issue one of the procfs
 799 fan commands: "enable", "disable", "level" or "watchdog", or if there
 800 are no writes to pwm1_enable (or to pwm1 *if and only if* pwm1_enable is
 801 set to 1, manual mode) within a configurable amount of time of up to
 802 120 seconds.  This functionality is called fan safety watchdog.
 803
 804 Note that the watchdog timer stops after it enables the fan.  It will be
 805 rearmed again automatically (using the same interval) when one of the
 806 above mentioned fan commands is received.  The fan watchdog is,
 807 therefore, not suitable to protect against fan mode changes made through
 808 means other than the "enable", "disable", and "level" procfs fan
 809 commands, or the hwmon fan control sysfs interface.
 810
 811 Procfs notes:
 812
 813 The fan may be enabled or disabled with the following commands:
 814
 815         echo enable  >/proc/acpi/ibm/fan
 816         echo disable >/proc/acpi/ibm/fan
 817
 818 Placing a fan on level 0 is the same as disabling it.  Enabling a fan
 819 will try to place it in a safe level if it is too slow or disabled.
 820
 821 The fan level can be controlled with the command:
 822
 823         echo 'level <level>' > /proc/acpi/ibm/fan
 824
 825 Where <level> is an integer from 0 to 7, or one of the words "auto" or
 826 "full-speed" (without the quotes).  Not all ThinkPads support the "auto"
 827 and "full-speed" levels.  The driver accepts "disengaged" as an alias for
 828 "full-speed", and reports it as "disengaged" for backwards
 829 compatibility.
 830
 831 On the X31 and X40 (and ONLY on those models), the fan speed can be
 832 controlled to a certain degree.  Once the fan is running, it can be
 833 forced to run faster or slower with the following command:
 834
 835         echo 'speed <speed>' > /proc/acpi/ibm/fan
 836
 837 The sustainable range of fan speeds on the X40 appears to be from about
 838 3700 to about 7350. Values outside this range either do not have any
 839 effect or the fan speed eventually settles somewhere in that range.  The
 840 fan cannot be stopped or started with this command.  This functionality
 841 is incomplete, and not available through the sysfs interface.
 842
 843 To program the safety watchdog, use the "watchdog" command.
 844
 845         echo 'watchdog <interval in seconds>' > /proc/acpi/ibm/fan
 846
 847 If you want to disable the watchdog, use 0 as the interval.
 848
 849 Sysfs notes:
 850
 851 The sysfs interface follows the hwmon subsystem guidelines for the most
 852 part, and the exception is the fan safety watchdog.
 853
 854 Writes to any of the sysfs attributes may return the EINVAL error if
 855 that operation is not supported in a given ThinkPad or if the parameter
 856 is out-of-bounds, and EPERM if it is forbidden.  They may also return
 857 EINTR (interrupted system call), and EIO (I/O error while trying to talk
 858 to the firmware).
 859
 860 Features not yet implemented by the driver return ENOSYS.
 861
 862 hwmon device attribute pwm1_enable:
 863         0: PWM offline (fan is set to full-speed mode)
 864         1: Manual PWM control (use pwm1 to set fan level)
 865         2: Hardware PWM control (EC "auto" mode)
 866         3: reserved (Software PWM control, not implemented yet)
 867
 868         Modes 0 and 2 are not supported by all ThinkPads, and the
 869         driver is not always able to detect this.  If it does know a
 870         mode is unsupported, it will return -EINVAL.
 871
 872 hwmon device attribute pwm1:
 873         Fan level, scaled from the firmware values of 0-7 to the hwmon
 874         scale of 0-255.  0 means fan stopped, 255 means highest normal
 875         speed (level 7).
 876
 877         This attribute only commands the fan if pmw1_enable is set to 1
 878         (manual PWM control).
 879
 880 hwmon device attribute fan1_input:
 881         Fan tachometer reading, in RPM.  May go stale on certain
 882         ThinkPads while the EC transitions the PWM to offline mode,
 883         which can take up to two minutes.  May return rubbish on older
 884         ThinkPads.
 885
 886 driver attribute fan_watchdog:
 887         Fan safety watchdog timer interval, in seconds.  Minimum is
 888         1 second, maximum is 120 seconds.  0 disables the watchdog.
 889
 890 To stop the fan: set pwm1 to zero, and pwm1_enable to 1.
 891
 892 To start the fan in a safe mode: set pwm1_enable to 2.  If that fails
 893 with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255
 894 would be the safest choice, though).
 895
 896
 897 EXPERIMENTAL: WAN
 898 -----------------
 899
 900 procfs: /proc/acpi/ibm/wan
 901 sysfs device attribute: wwan/enable
 902
 903 This feature is marked EXPERIMENTAL because the implementation
 904 directly accesses hardware registers and may not work as expected. USE
 905 WITH CAUTION! To use this feature, you need to supply the
 906 experimental=1 parameter when loading the module.
 907
 908 This feature shows the presence and current state of a W-WAN (Sierra
 909 Wireless EV-DO) device.
 910
 911 It was tested on a Lenovo Thinkpad X60. It should probably work on other
 912 Thinkpad models which come with this module installed.
 913
 914 Procfs notes:
 915
 916 If the W-WAN card is installed, the following commands can be used:
 917
 918         echo enable > /proc/acpi/ibm/wan
 919         echo disable > /proc/acpi/ibm/wan
 920
 921 Sysfs notes:
 922
 923         If the W-WAN card is installed, it can be enabled /
 924         disabled through the "wwan/enable" thinkpad-acpi device
 925         attribute, and its current status can also be queried.
 926
 927         enable:
 928                 0: disables WWAN card / WWAN card is disabled
 929                 1: enables WWAN card / WWAN card is enabled.
 930
 931         Note: this interface will be probably be superseeded by the
 932         generic rfkill class.
 933
 934 Multiple Commands, Module Parameters
 935 ------------------------------------
 936
 937 Multiple commands can be written to the proc files in one shot by
 938 separating them with commas, for example:
 939
 940         echo enable,0xffff > /proc/acpi/ibm/hotkey
 941         echo lcd_disable,crt_enable > /proc/acpi/ibm/video
 942
 943 Commands can also be specified when loading the thinkpad-acpi module,
 944 for example:
 945
 946         modprobe thinkpad_acpi hotkey=enable,0xffff video=auto_disable
 947
 948 Enabling debugging output
 949 -------------------------
 950
 951 The module takes a debug paramater which can be used to selectively
 952 enable various classes of debugging output, for example:
 953
 954          modprobe ibm_acpi debug=0xffff
 955
 956 will enable all debugging output classes.  It takes a bitmask, so
 957 to enable more than one output class, just add their values.
 958
 959         Debug bitmask           Description
 960         0x0001                  Initialization and probing
 961         0x0002                  Removal
 962
 963 There is also a kernel build option to enable more debugging
 964 information, which may be necessary to debug driver problems.
 965
 966 The level of debugging information output by the driver can be changed
 967 at runtime through sysfs, using the driver attribute debug_level.  The
 968 attribute takes the same bitmask as the debug module parameter above.
 969
 970 Force loading of module
 971 -----------------------
 972
 973 If thinkpad-acpi refuses to detect your ThinkPad, you can try to specify
 974 the module parameter force_load=1.  Regardless of whether this works or
 975 not, please contact ibm-acpi-devel@lists.sourceforge.net with a report.
 976
 977
 978 Sysfs interface changelog:
 979
 980 0x000100:       Initial sysfs support, as a single platform driver and
 981                 device.