Re: ideapad_laptop tablet mode toggle detection

[Armin Wolf <W_Armin@gmx.de>]

Am 05.03.23 um 23:59 schrieb Andrew Kallmeyer:

> On Sun, Mar 5, 2023 at 1:40 PM Armin Wolf <W_Armin@gmx.de> wrote:
>> Hi,
>>
>> could it be that bit 5 is set to disable the touchpad when the device switches
>> to tablet mode? I suspect that the query handler does the following:
>> 1. Notify VPC0 to disable the touchpad.
>> 2. Notify ACPI WMI, which does submit the necessary scancode for switching to tablet mode.
> I think you're right about this notification being for the touchpad,
> although at least on my machine
> there is no other touchpad switch. So this is identical for my machine
> specifically. In this function
> from the decompiled ACPI dump you can see VCP0 and WM00 notified:
>
> Method (_Q44, 0, NotSerialized)  // _Qxx: EC Query, xx=0x00-0xFF
> {
>     P80B = 0x44
>     Notify (VPC0, 0x80) // Status Change
>     WEID = 0xF4
>     Notify (WM00, 0x80) // Status Change
> }
>
> This WM00 device sounds like the WMI you're talking about, however I'm
> getting those errors
> about this device not existing in journalctl still. I was asking
> before about how to create this
> missing device but it's not clear to me if that is possible.
>
> kernel: ACPI BIOS Error (bug): Could not resolve symbol
> [\_SB.PC00.LPCB.EC0._Q44.WM00], AE_NOT_FOUND
>
> I searched in my .dsl files from the acpidump and wasn't able to find
> any of the 3 ideapad_wmi_ids
> listed in the driver. Maybe you have an idea of how to interface with
> this missing WM00 object though.

I was combing through the ACPI DSDT table inside the acpidump you provided,
and i found serveral PNP0C14 devices, which hold WMI methods, events and data.

The WMI GUIDs are encoded inside the associated _WDG buffers, you should therefore
only grep for parts of the GUIDs.
For example: GUID 06129D99-6083-4164-81AD-F092F9D773A6 -> grep "0xF0, 0x92"

When feeding the content of the buffers named WQxx to the bmfdec utility, i was able
to extract a description of each WMI object.

On of which (WMIY) is handling the "Lenovo Yoga Mode", which seems to handle the tablet
mode transitions. The MOF data is:

[WMI, Dynamic, Provider("WmiProv"), Locale("MS\\0x409"), Description("Lenovo Yoga Mode Change Event"), guid("{06129D99-6083-4164-81AD-F092F9D773A6}")]
class LENOVO_GSENSOR_EVENT : WMIEvent {
   [key, read] string InstanceName;
   [read] boolean Active;
   [WmiDataId(1), read, Description("Lenovo Yoga Mode Change Event")] uint32 ModeDataVal;
};

[WMI, Dynamic, Provider("WmiProv"), Locale("MS\\0x409"), Description("LENOVO_GSENSOR_DATA class"), guid("{09B0EE6E-C3FD-4243-8DA1-7911FF80BB8C}")]
class LENOVO_GSENSOR_DATA {
   [key, read] string InstanceName;
   [read] boolean Active;

   [WmiMethodId(1), Implemented, Description("Mode Data")] void GetUsageMode([out, Description("Mode Data")] uint32 Data);
   [WmiMethodId(2), Implemented, Description("Get Xaxis Value")] void GetXaxisValue([out, Description("Get Xaxis Value")] uint32 Data);
   [WmiMethodId(3), Implemented, Description("Get Yaxis Value")] void GetYaxisValue([out, Description("Get Yaxis Value")] uint32 Data);
   [WmiMethodId(4), Implemented, Description("Get Zaxis Value")] void GetZaxisValue([out, Description("Get Zaxis Value")] uint32 Data);
   [WmiMethodId(5), Implemented, Description("Base to Ground")] void GetAngle4Value([out, Description("Base to Ground")] uint32 Data);
   [WmiMethodId(6), Implemented, Description("Screen to Ground")] void GetAngle5Value([out, Description("Screen to Ground")] uint32 Data);
   [WmiMethodId(7), Implemented, Description("Screen to Base")] void GetAngle6Value([out, Description("Screen to Base")] uint32 Data);
};

While looking at _WED (used to get ModeDataVal) and WMAB (handles method calls on LENOVO_GSENSOR_DATA),
i assume that  only the first method (GetUsageMode) is implemented, and that ModeDataVal is used to tell
which value of LENOVO_GSENSOR_DATA has changed (hardwired to 1 on your device).

Maybe you can write a wmi driver which handles both WMI objects, so that you can find out what the values
returned by GetUsageMode mean. With a bit of luck, you can use this to implement tablet mode toggle detection.

BTW, what is the name of your notebook model?

Armin Wolf

>> Could you provide the output of "acpidump"? Because i suspect that the virtual key handling
>> is done using ACPI WMI, as many modern devices are using this approach. In this case, you
>> could experiment with ideapad_wmi_notify(), and maybe take a look at ideapad_wmi_ids[].
>>
>> Armin Wolf
> Here is the raw acpidump output: https://la.ask.systems/temp/acpidump.out
>
> - Andrew