Upstream has different patches for the same problem, and quirks are used as the following commits for 12.04:
lts-backport-quantal: b53729e72e31a7f8ecb5b025f5799f4f363dc757 precise: 95fbf65ed2ed69e5ee6ff0cf4c944091687673a0
As a result, it seems to add DMI to "video_dmi_table" and calls video_ignore_initial_backlight (as in #2). Therefore, we will need to find out which systems has the zero-brightness problem and add their DMI one by one.
Upstream has different patches for the same problem, and quirks are used as the following commits for 12.04:
lts-backport- quantal: b53729e72e31a7f 8ecb5b025f5799f 4f363dc757 5ee6ff0cf4c9440 91687673a0
precise: 95fbf65ed2ed69e
As a result, it seems to add DMI to "video_dmi_table" and calls video_ignore_ initial_ backlight (as in #2). Therefore, we will need to find out which systems has the zero-brightness problem and add their DMI one by one.