I'm running Linux Mint 15 on an Asus N56V Series laptop. new computer, new install of linux, fully updated. I am completely unable to change the brightness below a default 100%. I've done my research and tried:
1) xbacklight (after installing, $ xbacklight -set50, no change at all)
2) i've tried changing GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" then sudo update-grub then reboot. no change
3) i've tried changing GRUB_CMDLINE_LINUX="acpi_backlight=vendor" no change
4) i've tried the basic steps here: http://scienceblogs.com/gregladen/20...stay-upadjust/
5) i've opened the brightness setting from the system settings and, though i can move the slider bar around, it makes no changes to the monitor brightness
6) my Fn keys work for all other operations (keyboard backlight, volume controls, etc), but they do not work for brightness (f5 and f6. though i am able to turn the monitor off with Fn+f7)
7) i've installed the KDE package, including kgamma, though i seem unable to open it. or at least, to find the appropriate file to open to run the program.
for the sake of my burning eyes, i ask if anyone has any other suggestions that might work. or can point me on how to open kgamma so i can try that route
thank you!

not sure if this helps:
00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 (rev c4)
00:1c.3 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 4 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)
01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 635M] (rev a1)
03:00.0 Network controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01)
04:00.0 Ethernet controller: Qualcomm Atheros AR8161 Gigabit Ethernet (rev 10)

i've also tried Change the line that says
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
(slightly different than the above change). also did not work

one answer i found stated:
Add the line Option "registryDwords" "EnableBrightnessControl=1" in the appropriate Device section of the /etc/X11/xorg.conf file.
unfortunately, i do not have an xorg.conf file in /etc/X11