Date:	Tue, 25 Mar 2014 17:41:08 -0300
From:	Juan Manuel Cabo <juanmanuel.cabo@...il.com>
To:	Stefan Biereigel <security@...reigel-wb.de>,
	Kieran Clancy <clancy.kieran@...il.com>,
	Lan Tianyu <lantianyu1986@...il.com>
CC:	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r kernel org" <linux-kernel@...r.kernel.org>,
	Stefan Biereigel <stefan@...reigel.de>,
	Len Brown <lenb@...nel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	San Zamoyski <san@...snet.pl>,
	"D. Jansen" <dennis.jansen@....de>,
	Maurizio D'Addona <mauritiusdadd@...il.com>
Subject: Re: [REGRESSION 3.14-rc6] Samsung N150 lid does not "open" after
 suspend to RAM.

I can see a LID event being discarded here on resume:

      [  728.861983] ACPI : EC: <--- command = 0x84
      [  728.864062] ACPI : EC: ---> status = 0x09
      [  728.864070] ACPI : EC: ---> data = 0x5f
      [  728.864075] ACPI : EC: <--- command = 0x84
      [  728.868054] ACPI : EC: ---> status = 0x09
      [  728.868061] ACPI : EC: ---> data = 0x00
      [  728.868066] ACPI : EC: 1 stale EC events cleared
      [  728.868079] ACPI: Waking up from system sleep state S3

the 0x5F event means it's a LID change event (both in your dsdt and mine, look for: Q5F)

But there is still something I'm not sure of. So I will test that RC8 kernel tonight on my
laptop and let you all know. If RC8 still works on my laptop, then I guess the best would be
to make the EC fix specific to series 5, 7, 9 laptops, so your N150 is not affected anymore.
Thank you so much Stefan for your in-depth tests!

Cheers!
--
Juan Manuel Cabo



On 03/25/2014 05:24 PM, Stefan Biereigel wrote:
> Alright - as I have some spare time tonight, here is the dmesg of one
> sleep/resume cycle on an unpatched 3.14-rc8 tree with my usual config +
> dynamic debug enabled. After resuming, lid state was still "closed", so
> the bug was triggered (and the stale event is removed as stated).
>
> http://pastebin.ca/2679209
>
> You can find the "EC: 1 stale EC events cleared" Line @ Line 316. I
> really did not expect that much traffic from the EC, interesting to get
> some insight into that!
>
> Regarding other actions: The system notices removal of the AC cord when
> in sleep (xfce4-power-manager reports the correct symbol after the
> wakeup), so I guess this is working as it should (as it is handled by
> the _WAK-Routine??).
>
> Hope that helps!
> Stefan
>
>
> Am 25.03.2014 14:23, schrieb Kieran Clancy:
>> On Tue, Mar 25, 2014 at 8:04 PM, Lan Tianyu <lantianyu1986@...il.com> wrote:
>>> 2014-03-24 19:19 GMT+08:00 Stefan Biereigel <security@...reigel-wb.de>:
>>>> Hi,
>>>> thank you for the suggestion. The patch resolves the issue on my N150
>>>> when applied to a clean 3.14-rc7. Anyways I'm wondering if similar
>>>> problems to mine now exist on the Samsung Series 7/9 notebooks?
>>>>
>>>> Is any further action from my part required?
>>> Do you have these machines? If yes, please provide the output of
>>> dmidecode command.
>>>
>>> Cc guys  of commit ad332c8a.
>> Hi guys,
>>
>> That's a surprising side-effect, although I guess I shouldn't be
>> surprised by Samsung ACPI weirdness anymore.
>>
>> If we can, I'd like to get to the bottom of this rather than just turn
>> off this fix (which we know works for series 5, 7 and 9 without
>> problems).
>>
>>>>> 2014-03-24 15:50 GMT+08:00 Stefan Biereigel <security@...reigel-wb.de>:
>>>>>> Hi,
>>>>>>
>>>>>> starting with 3.14-rc6, the lid on my Samsung N150 behaves weird: My
>>>>>> system is set up, so that it should suspend to RAM as soon as the lid is
>>>>>> closed. Beginning with 3.14-rc6, the lid goes from "open" to "closed"
>>>>>> correctly the first time (and the system suspends), but after resuming
>>>>>> from standby (by opening the lid), the lid does not change to "open" again.
>>>>>> Of course, closing the lid again does not induce suspend to RAM then.
>>>>>> Opening the lid now (while not sleeping), makes ACPI notify the opening,
>>>>>> so I guess ACPI "misses" or discards the lid open event from the EC when
>>>>>> coming from sleep.
>>>>>> Now, closing the lid again does induce suspend to RAM. This behaviour is
>>>>>> reproducible: every other time, suspending works.
>>>>>>
>>>>>> This behaviour seems to be introduced by commit ad332c8a: ACPI / EC:
>>>>>> Clear stale EC events on Samsung systems.
>>>>>> Which was introduced after 3.14-rc5.
>>>>>>
>>>>>> When opening the lid to resume from standby, i see in dmesg:
>>>>>> Mar 23 22:12:04 little1 kernel: [ 7630.932074] ACPI : EC: 1 stale EC
>>>>>> events cleared
>>>>>> (which comes from drivers/acpi/ec.c)
>>>>>>
>>>>>> Seems to me, that the "open" event is cleared from the EC, but also
>>>>>> discarded instead of passed on. Shouldn't the correct behaviour be to
>>>>>> report all the pending events, read from the EC, as ACPI events? Can you
>>>>>> point me in a direction for fixing the issue cleanly, then I will try to
>>>>>> find a solution and prepare a patch for this issue.
>> Stefan, thank you for reporting this issue.
>>
>> Our rationale for discarding the events was that events queued during
>> sleep are probably no longer relevant. There could also be other
>> unwanted side-effects of blindly executing all of the old
>> instructions. But in your case, this assumption might be wrong.
>>
>> What command are you using to check if the lid is "open" or "closed"?
>> Is it because the screen is not waking up, or some other effect, or
>> just because it won't suspend again when it's re-closed?
>>
>> Do other events like AC plug/unplug affect any of this if you do them
>> during this bad state?
>>
>> I'd like to see exactly which EC command byte is being thrown away
>> here. If you do something like this (with dynamic debug enabled)
>>
>> echo -n 'file ec.c +p' | sudo tee /sys/kernel/debug/dynamic_debug/control
>>
>> You should get massively verbose EC stuff filling your dmesg, but I am
>> just interested in the EC read/write bytes just before and around the
>> "1 stale EC events cleared" message. Grab this out of dmesg before it
>> fills with other stuff.
>>
>> This will tell us what command we are being asked to run. If you can,
>> please do it a few times to see if it's the same command each time or
>> something different.
>>
>> You can turn the debug output off again with:
>>
>> echo -n 'file ec.c -p' | sudo tee /sys/kernel/debug/dynamic_debug/control
>>
>> I might also need a copy of your DSDT, if you can send me that
>> separately in another email (not to the list):
>>
>> cat /sys/firmware/acpi/tables/DSDT > .DSDT.aml
>>
>> Thank you,
>> Kieran.
>> --
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