Comment 67 for bug 935778

This proposed solution worked for me:

### SYSTEM INFO ###
# Model: Toshiba SATELLITE R830
# Kernel: 3.5.0-23-generic x86_64
# OS: Ubuntu 12.10 quantal

### KERNEL PARAMETER ###
$ grep vendor /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor"

### SCRIPT ###
#!/usr/bin/env sh
# /etc/pm/sleep.d/99toshiba

if [ $1 == suspend ]
then
        cat /sys/class/backlight/intel_backlight/brightness > /var/run/brightness
elif [ $1 == resume ]
then
        echo 3 > /sys/class/backlight/toshiba/brightness
        cat /var/run/brightness > /sys/class/backlight/intel_backlight/brightness
fi