Comment 3 for bug 191725

The sysfs battery change broke GetBrightness on dell latitude computers. The issue is there since ubuntu using this change, http://gitweb.freedesktop.org/?p=hal.git;a=commitdiff;h=4541abd23fd02118a1a7f8b825aed338d2a5d638 on 0.5.10, the current git version has the same bug

$ dbus-send --system --print-reply --dest=org.freedesktop.Hal `hal-find-by-capability --capability laptop_panel` org.freedesktop.Hal.Device.LaptopPanel.GetBrightness
Error org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

when running this command the hald log gets the error

"[20311]: 23:39:42.424 [D] addon-dell-backlight.cpp:231: Received GetBrightness DBUS call
process 20311: arguments to dbus_message_get_args() were incorrect, assertion "(error) == NULL || !dbus_error_is_set ((error))" failed in file dbus-message.c line 1667.
This is normally a bug in some application using the D-Bus library."

Reverting the change

$ dbus-send --system --print-reply --dest=org.freedesktop.Hal `hal-find-by-capability --capability laptop_panel` org.freedesktop.Hal.Device.LaptopPanel.GetBrightness
method return sender=:1.100 -> dest=:1.107 reply_serial=2
   int32 6

and the hald log has

"[20436]: 23:41:43.964 [D] addon-dell-backlight.cpp:231: Received GetBrightness DBUS call
[20436]: 23:41:43.968 [D] addon-dell-backlight.cpp:82: Reading 6 from the AC backlight register"