The _LID control method's initial returning value is not reliable.
The _LID control method is described to return the "current" lid state.
However the word of "current" has ambiguity, many BIOSen return the lid
state upon the last lid notification instead of returning the lid state
upon the last _LID evaluation. There won't be difference when the _LID
control method is evaluated during the runtime, the problem is its initial
returning value. When the BIOSen implement this control method with cached
value, the initial returning value is likely not reliable. There are simply
so many examples retuning "close" as initial lid state (Link 1), sending
this state to the userspace causes suspending right after booting/resuming.
Since the lid state is implemented by the BIOSen, the kernel lid driver has
no idea how it can be correct, this patch stops sending the initial lid
state to the userspace to try to avoid sending the wrong lid state to the
userspace to trigger such kind of wrong suspending. This actually reverts
the following commit introduced for fixing a Novell bug:
Commit: 23de5d9ef2
Subject: ACPI: button: send initial lid state after add and resume
Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941
Link: https://bugzilla.novell.com/show_bug.cgi?id=326814
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
c2dd420034