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SubjectRE: Keyboard regression by intel-vbtn
Date
> -----Original Message-----
> From: Hans de Goede <hdegoede@redhat.com>
> Sent: Wednesday, September 30, 2020 10:37
> To: Limonciello, Mario; Barnabás Pőcze; Andy Shevchenko
> Cc: platform-driver-x86@vger.kernel.org; linux-kernel@vger.kernel.org; Takashi
> Iwai
> Subject: Re: Keyboard regression by intel-vbtn
>
>
> [EXTERNAL EMAIL]
>
> Hi,
>
> On 9/30/20 5:12 PM, Limonciello, Mario wrote:
> >> -----Original Message-----
> >> From: Hans de Goede <hdegoede@redhat.com>
> >> Sent: Wednesday, September 30, 2020 8:28
> >> To: Limonciello, Mario; Barnabás Pőcze; Andy Shevchenko
> >> Cc: platform-driver-x86@vger.kernel.org; linux-kernel@vger.kernel.org;
> Takashi
> >> Iwai
> >> Subject: Re: Keyboard regression by intel-vbtn
> >>
> >>
> >> [EXTERNAL EMAIL]
> >>
> >> Hi,
> >>
> >> On 9/29/20 10:47 PM, Limonciello, Mario wrote:
> >>>>
> >>>> I requested on the Ubuntu bug for someone to provide these.
> >>>>
> >>>
> >>> Joe Barnett was kind enough to share two ACPI dumps to compare.
> >>> Not affected:
> >>>
> >>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1822394/+attachment/54153
> >> 18/+files/1.2.0.acpidump
> >>>
> >>> Affected:
> >>>
> >>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1822394/+attachment/54154
> >> 05/+files/1.13.0.acpidump
> >>
> >> Thank you, I took a look at these (before completing my allow-list fix),
> >> but there is not really much which stands out. The only related thing which
> >> stands out is that the 1.13.0 dsdt.dsl has this new bit:
> >>
> >>
> >> Case (0x08)
> >> {
> >> Return (^^PCI0.LPCB.H_EC.VGBI.VGBS ())
> >> }
> >>
> >> Inside the _DSM of the HIDD / INT33D5 device.
> >>
> >> Method (_DSM, 4, Serialized) // _DSM: Device-Specific Method
> >> {
> >> If ((Arg0 == ToUUID ("eeec56b3-4442-408f-a792-
> >> 4edd4d758054")))
> >>
> >>
> >> What is interesting here is that the PCI0.LPCB.H_EC.VGBI.VGBS object/method
> >> does not actually exist the correct path is:
> >>
> >> ^^PCI0.LPCB.ECDV.VGBI.VGBS
> >>
> >> So this does suggest that something around the VGBS handling changed
> >> (and since it points to a non existing ACPI object, possibly broke)
> >> in the newer BIOS version. But what exactly is going on on this XPS 2-in-1
> >> cannot really be derived from the acpidumps.
> >>
> >> Regards,
> >>
> >> Hans
> >
> > Looking through some publicly found content I think I might have figured out
> what
> > bight be the missing link.
> >
> > https://software.intel.com/sites/default/files/detecting-slate-clamshell-
> mode-and-screen-orientation-in-convertible-pc-1.pdf
> >
> > You can see that the device with CID PNP0C60 is supposed to indicate the
> presence
> > of a convertible hinge. We don't currently have anything that matches that
> _CID or _HID
> > in intel-vbtn.
> >
> > In the DSDT dump you can see that the status method for the INT33D3 device
> returns
> > 0x0F on 2-in-1.s
> >
> > Device (CIND)
> > {
> > Name (_HID, "INT33D3" /* Intel GPIO Buttons */) // _HID:
> Hardware ID
> > Name (_CID, "PNP0C60" /* Display Sensor Device */) // _CID:
> Compatible ID
> > Method (_STA, 0, Serialized) // _STA: Status
> > {
> > If ((OSYS >= 0x07DC))
> > {
> > Return (0x0F)
> > }
> >
> > Return (Zero)
> > }
> > }
> >
> > On a non 2-in-1 device I don't see this present. So I think we should have
> intel-vbtn
> > look for that INT33D3/PNP0C60 device to decide whether to offer the switch.
> >
> > Similarly as mentioned in that document I think that we should not be
> showing the
> > docking switch only when INT33D4/PNP0C70 is present and returns 0xF.
>
> That is a good find, thank you for digging into this and finding this.
>
> But it seems we have a typical case of the microsoft/intel example DSDT code
> being
> blindly copied everywhere here too:
>
> The chassis-type check was originally introduced by you in:
> commit de9647efeaa9 ("platform/x86: intel-vbtn: Only activate tablet mode
> switch on 2-in-1's")
>
> Some laptops such as the XPS 9360 support the intel-vbtn INT33D6
> interface but don't initialize the bit that intel-vbtn uses to
> represent switching tablet mode.
>
> By running this only on real 2-in-1's it shouldn't cause false
> positives.
>
> Fixes: 30323fb6d5 ("Support tablet mode switch")
>
> I have a XPS 9360 (which is not 2-in-1) acpidump and that has:
>
> Device (CIND)
> {
> Name (_HID, "INT33D3" /* Intel GPIO Buttons */) // _HID:
> Hardware ID
> Name (_CID, "PNP0C60" /* Display Sensor Device */) // _CID:
> Compatible ID
> Method (_STA, 0, Serialized) // _STA: Status
> {
> If ((OSYS >= 0x07DC))
> {
> Return (0x0F)
> }
>
> Return (Zero)
> }
> }
>
> And on an asus e200ha (also not a 2-in-1), where we were seeing
> similar problems, but then using asus custom WMI interface for
> getting SW_TABLET_MODE I see:
>
> Device (CIND)
> {
> Name (_HID, "INT33D3" /* Intel GPIO Buttons */) // _HID:
> Hardware ID
> Name (_CID, "PNP0C60" /* Display Sensor Device */) // _CID:
> Compatible ID
> Method (_STA, 0, Serialized) // _STA: Status
> {
> Return (0x0F)
> }
> }
>
> I have quite a few DSDTs (mostly byt/cht tablets or 2-in-1s though) and
> 65 of them define a "PNP0C60" device and only 1 unconditionally
> returns 0 from the _STA method for this device. Most others have
> an OSYS check. Some also check for some other, presumably BIOS
> configured variable, but by far most always return 0x0F, or do
> so after an OSYS check which will be true in our case.
>
> So I'm afraid that almost all devices which have the intel-vbtn (INT33D6)
> ACPI device will also have a PNP0C60 device with the exact same
> _STA method as found on the XPS 9360 and that this thus is not
> helpful.
>
> Regards,
>
> Hans

Well dang, that's unfortunate. I guess for now the allowlist is the
best solution then.

Thanks,
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