Quote Originally Posted by rorschachwalter View Post
The resolution issue is because the driver didn't properly install. Make sure you have "dkms" installed first as well as "linux-headers-`uname -r`" first. If you have "linux-headers-generic" installed, the nvidia driver will not work. So if you're still in that boat, you don't have to reinstall Ubuntu. Just remove the nvidia driver (and linux-headers-generic just for the heck of it), install linux-headers-`uname -r` first, then reinstall nvidia. Everything should work fine.

First, make sure nvidiabl is being loaded automatically by adding a line saying simply "nvidiabl" to /etc/modules.

The scripts I posted above weren't quite right, but they were really close. Here's what they should be:
/etc/acpi/nvidia_backlight_up.sh:
Code:
#!/bin/sh

test -f /sys/class/backlight/nvidia_backlight/brightness || exit 0

VAL=`cat /sys/class/backlight/nvidia_backlight/actual_brightness`
MAX=`cat /sys/class/backlight/nvidia_backlight/max_brightness`
STEP=10

VAL=`expr $VAL + $STEP`

if [ $VAL -gt $MAX ]; then
	VAL=$MAX
fi

echo -n $VAL > /sys/class/backlight/nvidia_backlight/brightness
/etc/acpi/nvidia_backlight_down.sh:
Code:
#!/bin/sh

test -f /sys/class/backlight/nvidia_backlight/brightness || exit 0

VAL=`cat /sys/class/backlight/nvidia_backlight/actual_brightness`
MIN=0
STEP=10

VAL=`expr $VAL - $STEP`

if [ $VAL -lt $MIN ]; then
	VAL=$MIN
fi

echo -n $VAL > /sys/class/backlight/nvidia_backlight/brightness
/etc/acpi/events/nvidia-brightness-down:
Code:
event=video LCD 00000087 00000000
action=/etc/acpi/nvidia_backlight_down.sh
/etc/acpi/events/nvidia-brightness-up:
Code:
event=video LCD 00000086 00000000
action=/etc/acpi/nvidia_backlight_up.sh
Then you have to make sure those scripts are executable:
Code:
sudo chmod +x /etc/acpi/nvidia_backlight_up.sh
sudo chmod +x /etc/acpi/nvidia_backlight_down.sh
You also need to have permissions to edit the brightness file itself (this was one of the problems I ran into -- the keys were running the script, but I didn't have permission to change the file so nothing happened). I'm not sure if this is the "proper" way to do things, but it at least works. Someone can correct me if I'm wrong and I'll edit this post:
Code:
sudo chown YOURUSERNAME /sys/class/backlight/nvidia_backlight/brightness
That should work for a Lenovo Y500. It's not quite a perfect workaround -- the brightness actually increases and decreases slightly past what the indicator shows, but it basically works and I think you'll be quite happy with it.

If it works for you exactly as I've written it up, please report back. If there was anything I didn't quite explain or that didn't quite work, please report back so I can edit this post for others as well.
Thanks for posting in detail.... The graphical brightness indicator seems to have a fixed number of steps I.e hotkey presses between min and max... If you increase your STEP size in the script so that the number of STEPs between 0 and max_brightness is the same as the number of steps the graphical indicator has, that might fix this minor issue.