42 lines
873 B
Markdown
42 lines
873 B
Markdown
# write-intel-brightness
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This is a script to control screen brightness on Lenovo ThinkPad X220 and similar after you changed PWM frequency by writing a custom value to 0xC8254 register. I use it with acpid.
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The script reads current PWM frequency from the register, calculates correct new brightness level for `/sys/class/backlight/intel_backlight/brightness` and writes it.
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### Usage
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To increase brightness:
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```
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write-intel-brightness +
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```
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To decrease:
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```
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write-intel-brightness -
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```
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### acpid example
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From `/etc/acpi/default.sh` on my Gentoo box:
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```
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case "$group" in
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video)
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case "$action" in
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brightnessup)
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/usr/local/bin/write-intel-brightness +
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;;
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brightnessdown)
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/usr/local/bin/write-intel-brightness -
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;;
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esac
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;;
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esac
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```
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### License
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MIT
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