Difference between revisions of "LCD Brightness"
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{{Stub}} | {{Stub}} | ||
| − | == | + | == Regular ACPI == |
This worked for my {{X61}}: | This worked for my {{X61}}: | ||
| Line 22: | Line 22: | ||
#!/bin/sh | #!/bin/sh | ||
xbacklight -inc 10% | xbacklight -inc 10% | ||
| + | === 2.6.26 kernel === | ||
| + | If you are using a 2.6.26 kernel, you are supposed to use the regular ACPI backlight control instead of thinkpad-acpi, on any Lenovo (Windows Vista-capable) ThinkPad. | ||
| + | |||
| + | Modify the kernel config by first disabling CONFIG_THINKPAD_ACPI_VIDEO and then enabling both CONFIG_VIDEO_OUTPUT_CONTROL and CONFIG_ACPI_VIDEO [http://www.nabble.com/T61-Brightness-keys-with-2.6.26-not-working-(NVIDIA)-td18577619.html] While you are at it, be sure to read the well-written help sections for the kernel config settings :) | ||
| + | |||
| + | == Thinkpad-ACPI == | ||
| + | |||
| + | If you have an older ThinkPad model, such as the {{T20}}, you may want to use [[thinkpad-acpi]]. | ||
| + | You can adjust the brightness of your screen by software using either procfs or sysfs. | ||
| + | |||
| + | If the following commands fail, you may want to try other module parameters for thinkpad-acpi. I had to use <tt>backlight_mode=1</tt> for example on my {{T20}}. | ||
| + | Just add the following line to your {{path|/etc/modprobe.conf}} | ||
| + | options thinkpad-acpi brightness_mode=1 | ||
| + | |||
| + | See the chapter <tt>LCD brightness control</tt> of {{path|Documentation/laptops/thinkpad-acpi.txt}} in the kernel sources for more informations. | ||
| + | |||
| + | ==== Using procfs ==== | ||
| + | |||
| + | To adjust the brightness to a certain level: | ||
| + | |||
| + | {{cmdroot|echo 'level 3' > /proc/acpi/ibm/brightness}} | ||
| + | |||
| + | Just one level up or down: | ||
| + | |||
| + | {{cmdroot|echo 'up' > /proc/acpi/ibm/brightness}} <br /> | ||
| + | {{cmdroot|echo 'down' > /proc/acpi/ibm/brightness}} | ||
| + | |||
| + | See {{path|/proc/acpi/ibm/brightness}} for a list of all available commands. | ||
| + | |||
| + | ==== Using sysfs ==== | ||
| + | |||
| + | The sysfs-interface allows more a flexible method of brightness control: | ||
| + | |||
| + | Get the current brightness level: | ||
| − | + | {{cmdroot|cat /sys/class/backlight/thinkpad_screen/actual_brightness}} | |
| − | + | Get the highest brightness level: | |
| + | |||
| + | {{cmdroot|cat /sys/class/backlight/thinkpad_screen/max_brightness}} | ||
| + | |||
| + | Adjust the brightness to a certain level: | ||
| − | + | {{cmdroot|echo 3 > /sys/class/backlight/thinkpad_screen/brightness}} | |
== Ubuntu 8.10 Intrepid Ibex == | == Ubuntu 8.10 Intrepid Ibex == | ||
The hardware keys work out of the box on a clean install of Ubuntu 8.10 Intrepid Ibex. No tweaking necessary. | The hardware keys work out of the box on a clean install of Ubuntu 8.10 Intrepid Ibex. No tweaking necessary. | ||
Revision as of 15:57, 19 December 2008
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Contents
Regular ACPI
This worked for my X61:
Once your brightness keys work, you can set the brightness by writing to the procfs:
# echo 100 > /proc/acpi/video/VID1/LCD0/brightness
using a script and acpid events. However this may lead to a bug (screen flickers) described on the Debian mailing list [[1]]. This bug is related to the X server as it does not occur on the tty1. To fix it change your xrandr backlight control to native:
$ $xrandr --output LVDS --set BACKLIGHT_CONTROL native
For my X61, these following scripts from this japanese site helped:
% cat /etc/acpi/video_brightnessdown.sh #!/bin/sh xbacklight -dec 10%
% cat /etc/acpi/video_brightnessup.sh #!/bin/sh xbacklight -inc 10%
2.6.26 kernel
If you are using a 2.6.26 kernel, you are supposed to use the regular ACPI backlight control instead of thinkpad-acpi, on any Lenovo (Windows Vista-capable) ThinkPad.
Modify the kernel config by first disabling CONFIG_THINKPAD_ACPI_VIDEO and then enabling both CONFIG_VIDEO_OUTPUT_CONTROL and CONFIG_ACPI_VIDEO [2] While you are at it, be sure to read the well-written help sections for the kernel config settings :)
Thinkpad-ACPI
If you have an older ThinkPad model, such as the T20, you may want to use thinkpad-acpi. You can adjust the brightness of your screen by software using either procfs or sysfs.
If the following commands fail, you may want to try other module parameters for thinkpad-acpi. I had to use backlight_mode=1 for example on my T20. Just add the following line to your /etc/modprobe.conf
options thinkpad-acpi brightness_mode=1
See the chapter LCD brightness control of Documentation/laptops/thinkpad-acpi.txt in the kernel sources for more informations.
Using procfs
To adjust the brightness to a certain level:
# echo 'level 3' > /proc/acpi/ibm/brightness
Just one level up or down:
# echo 'up' > /proc/acpi/ibm/brightness
# echo 'down' > /proc/acpi/ibm/brightness
See /proc/acpi/ibm/brightness for a list of all available commands.
Using sysfs
The sysfs-interface allows more a flexible method of brightness control:
Get the current brightness level:
# cat /sys/class/backlight/thinkpad_screen/actual_brightness
Get the highest brightness level:
# cat /sys/class/backlight/thinkpad_screen/max_brightness
Adjust the brightness to a certain level:
# echo 3 > /sys/class/backlight/thinkpad_screen/brightness
Ubuntu 8.10 Intrepid Ibex
The hardware keys work out of the box on a clean install of Ubuntu 8.10 Intrepid Ibex. No tweaking necessary.
