I have an HP 510 laptop with Ubuntu 12.04.
I have all the correct settings for suspending when the lid is closed, as far as I can tell, so I think it's a problem with detecting the event.
The way it "should" be detected, from what I can see, is a little hardware switch that is pushed when the lid closes. This switch manually puts off the backlight, and sends the suspend signal. All I can think is that the signal isn't being properly interpreted.
Can anyone suggest a fix?
I tested whether the button was actually working based on the suggestion by josinalvo, and I found that in the directory
/proc/acpi/button/lid/ there is no
LID directory. There is, however, a
C1CF folder, and in it is a state file.
When using the this file instead of
LID, I discovered that, no, when I close the lid, the state does not change.
The full path is: '/proc/acpi/button/lid/C1CF/state
Update 2 I'm now running Xubuntu 12.10, (Unity was to slow) but I still have the same problem.