brightness not getting adjusted by brightness control keys.

I am using ubuntu 12.04 in my sony vaio VPCEH38FN E series laptop. The brightness is always set to maximum and when i try to adjust it by brightness contol keys ,no effect is there.There is no such problem when i run windows. What to do?

Hello and welcome to the forums.

What video card do you have and which driver are you using? Can you open a terminal window, run the following commands and post back the results:

Code:

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sudo lspci -vnn | grep -A12 VGA

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Code:

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cat /proc/cmdline

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Code:

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

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Code:

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cat /var/log/dmesg | grep -i brightness

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Lets see what you've got.