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My laptop has
Intel(R) Core(TM) i5-4200U CPU @ 1.60GHz, 4G RAM, Haswell-ULT Integrated Graphics Controller
Only thing unusual is when I installed Ubuntu 14.04 LTS, I edited grub as
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
I searched about brightness control issues, and they said
/sys/class/backlight and do something',
but there was nothing in there. I opened terminal and typed
ls -a /sys/class/backlight
but the output was
The brightness is too high so my battery is running so fast, but I don't know what i have to do.