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

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Date:	Tue, 21 Jul 2015 00:22:42 +0000
From:	"Zheng, Lv" <lv.zheng@...el.com>
To:	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

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