Thread: How to Increase the PWM frequency of backlight

i bought dell n4030 , can feel screen isn't confortable. pwm frequency of backlight has lower frequency , if stay long time front laptop may cause headache.

brightness can decrease , increase changing pulse width, frequency it's same. wanna change, increasing.

think it's possible if change in kernel. found archive may related this.

/usr/src/linux-headers-2.6.38-8-generic/include/linux/pwm_backlight.h

/*
* generic pwm backlight driver data - see drivers/video/backlight/pwm_bl.c
*/
#ifndef __linux_pwm_backlight_h
#define __linux_pwm_backlight_h

struct platform_pwm_backlight_data {
int pwm_id;
unsigned int max_brightness;
unsigned int dft_brightness;
unsigned int lth_brightness;
unsigned int pwm_period_ns;
int (*init)(struct device *dev);
int (*notify)(struct device *dev, int brightness);
void (*exit)(struct device *dev);
};

#endif

maybe can change variable unsigned int pwm_period_ns; decreasing period, , taking 1 upper frequency.

can me it?

all.

have checked switches in bios or acpitool?

sudo apt-get install acpitool
man acpitool
acpitool -e

check variables can set in:

/proc/acpi/video/vid/lcd0

location of brightness/pwm variable may different posted since i'm on thinkpad, video display stuff located in /proc/acpi/video

if find it, use echo statement poke correct value controlling file.

here's script called blink.sh use blink thinklight. use skype chat notification.


#!/bin/bash
# script blinking thinklight
# needs run root
# depends on /usr/bin/seq

# if [ $# -ne 2 ] ; then
# echo “usage: $0 <nbrofblinks> <frequency>”
# exit 1
# fi

nbr_of_blinks=$1
frequency=$2
thinklight=/proc/acpi/ibm/light

in `seq $nbr_of_blinks`
do
echo on > $thinklight
sleep $frequency
echo off > $thinklight
sleep $frequency
done

Forum The Ubuntu Forum Community Ubuntu Official Flavours Support Hardware [other] How to Increase the PWM frequency of backlight

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