Comment 18 for bug 562005

Here are the relevant parts of my lshal output:

udi = '/org/freedesktop/Hal/devices/computer_backlight_0'
  info.addons = {'hald-addon-generic-backlight'} (string list)
  info.capabilities = {'laptop_panel'} (string list)
  info.category = 'laptop_panel' (string)
  info.interfaces = {'org.freedesktop.Hal.Device.LaptopPanel'} (string list)
  info.parent = '/org/freedesktop/Hal/devices/computer' (string)
  info.product = 'Generic Backlight Device' (string)
  info.subsystem = 'backlight' (string)
  info.udi = '/org/freedesktop/Hal/devices/computer_backlight_0' (string)
  laptop_panel.access_method = 'general' (string)
  laptop_panel.brightness_in_hardware = true (bool)
  laptop_panel.num_levels = 1 (0x1) (int)
  linux.hotplug_type = 2 (0x2) (int)
  linux.subsystem = 'backlight' (string)
  linux.sysfs_path = '/sys/devices/virtual/backlight/thinkpad_screen' (string)

udi = '/org/freedesktop/Hal/devices/computer_backlight'
  info.addons = {'hald-addon-generic-backlight'} (string list)
  info.capabilities = {'laptop_panel'} (string list)
  info.category = 'laptop_panel' (string)
  info.interfaces = {'org.freedesktop.Hal.Device.LaptopPanel'} (string list)
  info.parent = '/org/freedesktop/Hal/devices/computer' (string)
  info.product = 'Generic Backlight Device' (string)
  info.subsystem = 'backlight' (string)
  info.udi = '/org/freedesktop/Hal/devices/computer_backlight' (string)
  laptop_panel.access_method = 'general' (string)
  laptop_panel.brightness_in_hardware = true (bool)
  laptop_panel.num_levels = 16 (0x10) (int)
  linux.hotplug_type = 2 (0x2) (int)
  linux.subsystem = 'backlight' (string)
  linux.sysfs_path = '/sys/devices/virtual/backlight/acpi_video0' (string)

I don't know why I have both a "computer_backlight" and a computer_backlight_0" entry. This is from a fresh install of Lucid RC on a Thinkpad W510 with the latest 195 series nvidia driver from the Ubuntu repo. It reports 16 levels, which is what I get in Windows (0 to 15). Right now I can only control brightness by switching to a TTY. i get 16 different levels there, and the up and down increments are the same. I don't currently have the "EnableBrightControl" option set in my xorg.conf.