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Diffstat (limited to 'Documentation/laptops/thinkpad-acpi.txt')
| -rw-r--r-- | Documentation/laptops/thinkpad-acpi.txt | 160 |
1 files changed, 108 insertions, 52 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index aafcaa634191..75afa1229fd7 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -1,7 +1,7 @@ ThinkPad ACPI Extras Driver - Version 0.23 - April 10th, 2009 + Version 0.24 + December 11th, 2009 Borislav Deianov <borislav@users.sf.net> Henrique de Moraes Holschuh <hmh@hmh.eng.br> @@ -460,6 +460,8 @@ event code Key Notes For Lenovo ThinkPads with a new BIOS, it has to be handled either by the ACPI OSI, or by userspace. + The driver does the right thing, + never mess with this. 0x1011 0x10 FN+END Brightness down. See brightness up for details. @@ -582,46 +584,15 @@ with hotkey_report_mode. Brightness hotkey notes: -These are the current sane choices for brightness key mapping in -thinkpad-acpi: +Don't mess with the brightness hotkeys in a Thinkpad. If you want +notifications for OSD, use the sysfs backlight class event support. -For IBM and Lenovo models *without* ACPI backlight control (the ones on -which thinkpad-acpi will autoload its backlight interface by default, -and on which ACPI video does not export a backlight interface): - -1. Don't enable or map the brightness hotkeys in thinkpad-acpi, as - these older firmware versions unfortunately won't respect the hotkey - mask for brightness keys anyway, and always reacts to them. This - usually work fine, unless X.org drivers are doing something to block - the BIOS. In that case, use (3) below. This is the default mode of - operation. - -2. Enable the hotkeys, but map them to something else that is NOT - KEY_BRIGHTNESS_UP/DOWN or any other keycode that would cause - userspace to try to change the backlight level, and use that as an - on-screen-display hint. - -3. IF AND ONLY IF X.org drivers find a way to block the firmware from - automatically changing the brightness, enable the hotkeys and map - them to KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN, and feed that to - something that calls xbacklight. thinkpad-acpi will not be able to - change brightness in that case either, so you should disable its - backlight interface. - -For Lenovo models *with* ACPI backlight control: - -1. Load up ACPI video and use that. ACPI video will report ACPI - events for brightness change keys. Do not mess with thinkpad-acpi - defaults in this case. thinkpad-acpi should not have anything to do - with backlight events in a scenario where ACPI video is loaded: - brightness hotkeys must be disabled, and the backlight interface is - to be kept disabled as well. This is the default mode of operation. - -2. Do *NOT* load up ACPI video, enable the hotkeys in thinkpad-acpi, - and map them to KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN. Process - these keys on userspace somehow (e.g. by calling xbacklight). - The driver will do this automatically if it detects that ACPI video - has been disabled. +The driver will issue KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN events +automatically for the cases were userspace has to do something to +implement brightness changes. When you override these events, you will +either fail to handle properly the ThinkPads that require explicit +action to change backlight brightness, or the ThinkPads that require +that no action be taken to work properly. Bluetooth @@ -1121,25 +1092,103 @@ WARNING: its level up and down at every change. -Volume control -- /proc/acpi/ibm/volume ---------------------------------------- +Volume control (Console Audio control) +-------------------------------------- + +procfs: /proc/acpi/ibm/volume +ALSA: "ThinkPad Console Audio Control", default ID: "ThinkPadEC" + +NOTE: by default, the volume control interface operates in read-only +mode, as it is supposed to be used for on-screen-display purposes. +The read/write mode can be enabled through the use of the +"volume_control=1" module parameter. + +NOTE: distros are urged to not enable volume_control by default, this +should be done by the local admin only. The ThinkPad UI is for the +console audio control to be done through the volume keys only, and for +the desktop environment to just provide on-screen-display feedback. +Software volume control should be done only in the main AC97/HDA +mixer. + + +About the ThinkPad Console Audio control: + +ThinkPads have a built-in amplifier and muting circuit that drives the +console headphone and speakers. This circuit is after the main AC97 +or HDA mixer in the audio path, and under exclusive control of the +firmware. + +ThinkPads have three special hotkeys to interact with the console +audio control: volume up, volume down and mute. + +It is worth noting that the normal way the mute function works (on +ThinkPads that do not have a "mute LED") is: -This feature allows volume control on ThinkPad models which don't have -a hardware volume knob. The available commands are: +1. Press mute to mute. It will *always* mute, you can press it as + many times as you want, and the sound will remain mute. + +2. Press either volume key to unmute the ThinkPad (it will _not_ + change the volume, it will just unmute). + +This is a very superior design when compared to the cheap software-only +mute-toggle solution found on normal consumer laptops: you can be +absolutely sure the ThinkPad will not make noise if you press the mute +button, no matter the previous state. + +The IBM ThinkPads, and the earlier Lenovo ThinkPads have variable-gain +amplifiers driving the speakers and headphone output, and the firmware +also handles volume control for the headphone and speakers on these +ThinkPads without any help from the operating system (this volume +control stage exists after the main AC97 or HDA mixer in the audio +path). + +The newer Lenovo models only have firmware mute control, and depend on +the main HDA mixer to do volume control (which is done by the operating +system). In this case, the volume keys are filtered out for unmute +key press (there are some firmware bugs in this area) and delivered as +normal key presses to the operating system (thinkpad-acpi is not +involved). + + +The ThinkPad-ACPI volume control: + +The preferred way to interact with the Console Audio control is the +ALSA interface. + +The legacy procfs interface allows one to read the current state, +and if volume control is enabled, accepts the following commands: echo up >/proc/acpi/ibm/volume echo down >/proc/acpi/ibm/volume echo mute >/proc/acpi/ibm/volume + echo unmute >/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. +The <level> number range is 0 to 14 although not all of them may be +distinct. To unmute the volume after the mute command, use either the +up or down command (the level command will not unmute the volume), or +the unmute command. + +You can use the volume_capabilities parameter to tell the driver +whether your thinkpad has volume control or mute-only control: +volume_capabilities=1 for mixers with mute and volume control, +volume_capabilities=2 for mixers with only mute control. + +If the driver misdetects the capabilities for your ThinkPad model, +please report this to ibm-acpi-devel@lists.sourceforge.net, so that we +can update the driver. + +There are two strategies for volume control. To select which one +should be used, use the volume_mode module parameter: volume_mode=1 +selects EC mode, and volume_mode=3 selects EC mode with NVRAM backing +(so that volume/mute changes are remembered across shutdown/reboot). -The ALSA mixer interface to this feature is still missing, but patches -to add it exist. That problem should be addressed in the not so -distant future. +The driver will operate in volume_mode=3 by default. If that does not +work well on your ThinkPad model, please report this to +ibm-acpi-devel@lists.sourceforge.net. + +The driver supports the standard ALSA module parameters. If the ALSA +mixer is disabled, the driver will disable all volume functionality. Fan control and monitoring: fan speed, fan enable/disable @@ -1405,6 +1454,7 @@ to enable more than one output class, just add their values. 0x0008 HKEY event interface, hotkeys 0x0010 Fan control 0x0020 Backlight brightness + 0x0040 Audio mixer/volume control There is also a kernel build option to enable more debugging information, which may be necessary to debug driver problems. @@ -1465,3 +1515,9 @@ Sysfs interface changelog: and it is always able to disable hot keys. Very old thinkpads are properly supported. hotkey_bios_mask is deprecated and marked for removal. + +0x020600: Marker for backlight change event support. + +0x020700: Support for mute-only mixers. + Volume control in read-only mode by default. + Marker for ALSA mixer support. |