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I am using a Sony Vaio SVE15113EN laptop. Recently I installed Ubuntu 14.04 and found out that I am unable to adjust my display brightness slider. The brightness is so high that I am unable to use the laptop while using Ubuntu. I request the experts here to guide me to resolve this issue. Thanking you all in advance for your time and replies. I have tried all the below commands, but nothing happened:

cat /proc/cmdline

  1. Your video card and driver: Code:

sudo lspci -vnn | grep -A12 VGA

  1. You backlight interfaces: Code:

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

echo 15 | sudo tee /sys/class/backlight/acpi_video0/brightness echo 6 | sudo tee /sys/class/backlight/acpi_video0/brightness

Code:

echo 2441 | sudo tee /sys/class/backlight/intel_backlight/brightness echo 4882 | sudo tee /sys/class/backlight/intel_backlight/brightnes

acpi_listen sony/hotkey SNC 00000001 00000011 sony/hotkey SNC 00000001 0000003b sony/hotkey SNC 00000001 00000010 sony/hotkey SNC 00000001 0000003b

But instead of SNC I got SNY.

Create the following files with the following content (you will need root privileges to do this, so for each file, run "gksu gedit " where is: )

/etc/acpi/events/sony-brightness-up Code:

event=sony/hotkey SNC 00000001 00000011 action=/etc/acpi/brightup.sh

/etc/acpi/events/sony-brightness-down Code:

event=sony/hotkey SNC 00000001 00000010 action=/etc/acpi/brightdown.sh

/etc/acpi/brightdown.sh Code:

!/bin/bash

curr=cat /sys/class/backlight/intel_backlight/actual_brightness if [ $curr -gt 406 ]; then curr=$((curr-406)); echo $curr > /sys/class/backlight/intel_backlight/brightness; fi

/etc/acpi/brightup.sh Code:

!/bin/bash

curr=cat /sys/class/backlight/intel_backlight/actual_brightness if [ $curr -lt 4477 ]; then curr=$((curr+406)); echo $curr > /sys/class/backlight/intel_backlight/brightness; fi

Then, make all 4 of those scripts executable by running the following commands: Code:

sudo chmod +x /etc/acpi/events/sony-brightness-up sudo chmod +x /etc/acpi/events/sony-brightness-down sudo chmod +x /etc/acpi/brightdown.sh sudo chmod +x /etc/acpi/brightup.sh

And finally, restart acpid: Code:

sudo service acpid restart

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