linux-kernel - Re: Ghost Lid switch on Baytrail tablet

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Message-ID: <55ADDED9.8060901@intel.com>
Date:	Tue, 21 Jul 2015 13:55:37 +0800
From:	Aaron Lu <aaron.lu@...el.com>
To:	"Zheng, Lv" <lv.zheng@...el.com>,
	Bastien Nocera <hadess@...ess.net>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:	"dev@...utier.fr" <dev@...utier.fr>
Subject: Re: Ghost Lid switch on Baytrail tablet

On 07/21/2015 09:30 AM, Zheng, Lv wrote:
> Hi,
> 
> If the issue is already identified and confirmed:
> For example, you've confirmed the QR_EC(0x14) can only arrive when the keyboard accessory is plugged in.
> Then please ignore my previous reply.
> I don't have idea about handling a LID that always returns "closed" when the keyboard accessory is not plugged in.

Perhaps the LID status should be ignored when the device is in tablet
mode?

In the meantime, I took a look at two tablets here: ASUS T100 and Onda
V975W, both are baytrail-T tablet while the T100 has a keyboard dock.
For T100, its _LID return the value of GPO2.LIDZ, which has an initial
value of 1: "Name(LIDZ, One)" and on LID events, LIDZ will be assigned
proper value; and for Onda V975W, it doesn't define the LID acpi device.
So these two devices don't have this problem.

-Aaron

> 
> Thanks
> -Lv
> 
>> From: Zheng, Lv
>> Sent: Tuesday, July 21, 2015 8:23 AM
>>
>> Hi,
>>
>> The _LID returns LIDS:
>>         Device (LID)
>>         {
>>             Name (_HID, EisaId ("PNP0C0D") /* Lid Device */)  // _HID: Hardware ID
>>             Name (LIDS, Zero)
>>             Method (_LID, 0, NotSerialized)  // _LID: Lid Status
>>             {
>>                 Return (LIDS) /* \_SB_.LID_.LIDS */
>>             }
>>         }
>> All LIDS related code can be found:
>> 	Line 132:         LIDS,   8,
>> 	Line 5400:                         PARM |= (LIDS << 0x10)
>> 	Line 5566:                         PARM = (LIDS << 0x08)
>> 	Line 11792:             ^^LID.LIDS = Zero
>> *	Line 11802:             ^^LID.LIDS = One
>> 	Line 11906:             Name (LIDS, Zero)
>> 	Line 11909:                 Return (LIDS) /* \_SB_.LID_.LIDS */
>> The value is only set by Q14 (marked by * above):
>>         Method (Q14, 0, NotSerialized)
>>         {
>>             P8XH (One, 0xBB)
>>             P8XH (Zero, 0x14)
>>             ^^LID.LIDS = One
>>             Notify (LID, 0x80) // Status Change
>>             P8XH (One, 0xBB)
>>             P8XH (Zero, 0xA4)
>>         }
>> If QR_EC(0x14) cannot arrive to the OSPMs as early as possible, then the default LIDS=0 value may cause problem.
>> We need EC debug log to track if QR_EC(0x14) can arrive earlier.
>>
>> You can uncomment the following line from drivers/acpi/ec.c and rebuild the kernel:
>> /* #define DEBUG */
>>
>> Send the dmesg output (before suspending) to us.
>>
>> Thanks and best regards
>> -Lv
>>
>>> -----Original Message-----
>>> From: Bastien Nocera [mailto:hadess@...ess.net]
>>> Sent: Sunday, July 19, 2015 8:43 AM
>>> To: Rafael J. Wysocki; Len Brown; linux-acpi@...r.kernel.org; linux-kernel@...r.kernel.org
>>> Cc: dev@...utier.fr
>>> Subject: Ghost Lid switch on Baytrail tablet
>>>
>>> Hey,
>>>
>>> This tablet:
>>> http://www.amazon.com/WinBook-10-1-Inch-Windows-full-size-Display/dp/B00N9ZG5U2/
>>> doesn't have a physical lid switch unless you plug the keyboard accessory to it.
>>>
>>> But it thinks that there is a lid, and that it's closed, making logind
>>> suspend the machine after about 30 seconds.
>>>
>>> I'm currently testing this on a 4.0 kernel, as there have been
>>> regressions on Baytrail with 4.1 and 4.2rcs.
>>>
>>> The DSDT for that tablet:
>>> https://people.gnome.org/~hadess/Winbook%20TW100%20DSDT.dsl
>>>
>>> Any ideas how to handle this sort of device?
>>>
>>> Cheers
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> 

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