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Diffstat (limited to 'Documentation/laptops')
| -rw-r--r-- | Documentation/laptops/thinkpad-acpi.txt | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index 76cb428435d..a77da28a6f8 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -571,6 +571,47 @@ netlink interface and the input layer interface, and don't bother at all with hotkey_report_mode. +Brightness hotkey notes: + +These are the current sane choices for brightness key mapping in +thinkpad-acpi: + +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). + Bluetooth --------- @@ -1090,6 +1131,15 @@ it there will be the following attributes: dim the display. +WARNING: + + Whatever you do, do NOT ever call thinkpad-acpi backlight-level change + interface and the ACPI-based backlight level change interface + (available on newer BIOSes, and driven by the Linux ACPI video driver) + at the same time. The two will interact in bad ways, do funny things, + and maybe reduce the life of the backlight lamps by needlessly kicking + its level up and down at every change. + Volume control -- /proc/acpi/ibm/volume --------------------------------------- |