linux-kernel - Samsung N145 Plus lid state issue on sleep

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Date:	Thu, 26 Sep 2013 18:25:00 +0100
From:	Nick Warne <nick@...icks.net>
To:	linux-kernel@...r.kernel.org, linux-apci@...r.kernel.org
Subject: Samsung N145 Plus lid state issue on sleep

Hi all,

I have a strange problem, which has been on going on for ages, and I finally decided to look at it (as it is a pain in the arse).

Brief details:

Samsung N145 Plus running Slack 14 with handbuilt kernel
Kernel: Linux 3.11.1 #3 SMP Mon Sep 23 19:09:00 BST 2013 i686 Intel(R) Atom(TM) CPU N455   @ 1.66GHz GenuineIntel GNU/Linux
I have no modules built in (.config on request if it helps).

This issue also happened with 'distro' kernel builds... so either it is BIOS issue or hardware fault.  But just in case:

Boot laptop into console - no X - so running pure acpi events.

cat /proc/acpi/button/lid/LID0/state
state:      open

shut lid

laptop goes to sleep all great.

open lid.  Laptop wakes up, video, wlan0 all comes on line, everything hunky dory - but:

cat /proc/acpi/button/lid/LID0/state
state:      closed

The lid is open, of course!

OK, shut lid.  LCD backlight goes off (so something knows the lid is shut), but no sleep event.  Open lid after a few seconds (maybe 10), and screen lights up and then laptop goes to sleep!

Shut lid (wait for a few seconds), open lid, laptop wakes up fine again, and now:

cat /proc/acpi/button/lid/LID0/state
state:      open

!

So it appears that closing lid flags 'closed' state but opening it doesn't flag 'open' state... unless I then close it again and open which then flags 'closed' state when open so goes to sleep.  So no open it again, and 'state now reports 'open' again.  At this point, back to square one (confused?  I am!).

Using Fn [sleep] in any mode above works OK.  The same happens in X using xfce4 PM or similar.

What is confusing me is that something can see the lid flapping as backlight works on lid open/close.

acpi_listen reports the events as described above, but I can't work out how to record the events when a sleep :)

And ideas/help etc. appreciated, and also I am in the position to be able to debug (with help, of course)!

Thanks,

Nick
-- 
http://linicks.net/
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