path: root/Documentation/laptops
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authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>2009-12-09 01:36:24 +0000
committerLen Brown <len.brown@intel.com>2009-12-09 15:45:30 -0500
commit347a26860e2293b1347996876d3550499c7bb31f (patch)
treeedd7781ecd31f9771b8adf4458eecdd6ed0e9607 /Documentation/laptops
parent90765c6aee568137521ba19347c744b5abde8161 (diff)
thinkpad-acpi: issue backlight class events
Take advantage of the new events capabilities of the backlight class to notify userspace of backlight changes. This depends on "backlight: Allow drivers to update the core, and generate events on changes", by Matthew Garrett. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: Matthew Garrett <mjg@redhat.com> Cc: Richard Purdie <rpurdie@linux.intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation/laptops')
1 files changed, 12 insertions, 39 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index aafcaa634191..f5056c7fb5be 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -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
+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.
@@ -1465,3 +1436,5 @@ 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.

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