Comment 9 for bug 345318

Here is the output from lshal for my backlight:

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.num_levels = 10 (0xa) (int)
  linux.hotplug_type = 2 (0x2) (int)
  linux.subsystem = 'backlight' (string)
  linux.sysfs_path = '/sys/devices/platform/acer-wmi/backlight/acer-wmi' (string)

The num_level is correctly detected as 10 steps. I'm assuming this is how gpm gets its number of steps, before adjusting for macbooks via the new patch that is.