Re: ideapad_laptop tablet mode toggle detection

[Armin Wolf <W_Armin@gmx.de>]

Am 04.03.23 um 21:14 schrieb Maximilian Luz:

> Hi,
>
> On 3/4/23 06:46, Andrew Kallmeyer wrote:
>> I'm still wondering about that AE_NOT_FOUND error about the WM00
>> device> though. It seems that the ACPI expects the kernel to define
>> this WM00> device as an extension point. In the DSDT I found:> >
>> External (_SB_.WM00, DeviceObj)
> AFAIK this just means that it's external to this table (i.e. the DSDT I
> assume), not that the kernel needs to define it (I'm not sure if
> that's even an
> option in the ACPI spec or ACPICA). So it should be in some SSDT or
> the ACPI
> implementation is broken (unless defining devices from the kernel is
> really an
> option and I'm just misinformed).
>
>> Scope (\_SB.PC00.LPCB.EC0)
>> {
>>
>>      Method (_Q44, 0, NotSerialized)  // _Qxx: EC Query, xx=0x00-0xFF
>>      {
>>         P80B = 0x44
>>         Notify (VPC0, 0x80) // Status Change
>>         WEID = 0xF4
>>         Notify (WM00, 0x80) // Status Change
>>      }
>> ...
>>      Device (VPC0)
>>      {
>>          Name (_HID, "VPC2004")  // _HID: Hardware ID
>>          Name (_UID, Zero)  // _UID: Unique ID
>>          Name (_VPC, 0x7C0DE114)
>>          Name (VPCD, Zero)
>>
>>
>> Additionally two other _Qxx methods (11 and 12) Notify the same
>> two devices. These other two are the brightness up and down keys.
>> The only difference is they set those two variables differently so I'll
>> have to read those variables as well to differentiate screen flips.
>> Right now my module actually detects both screen flips and
>> brightness key presses.
>
> I believe that makes sense, given the ACPI code.
>
>> I haven't been able to figure out how to create the WM00 device,
>> I'm not even sure that's a thing in ACPI. I also haven't seen how
>> to read those variables.
>
> You can use acpi_evaluate_object() and acpi_evaluate_object_typed()
> for that.
>
>> Is it okay to reuse the events sent to this
>> VPC0 device or am I intercepting the events from some other
>> functionality? Any pointers would be greatly appreciated.
>
> I guess that depends on the VPC0 device. If it doesn't have a driver
> already
> (which you can check by getting the HID of that device from the DSDT and
> grep-ing for it in the kernel source), you can write your own driver
> against
> it, install the notify-handler, and do basically whatever you want.
> You're not
> intercepting/blocking anything by that. If there already is a driver,
> you'll
> have to check what that does and if you can integrate your
> functionality there.
>
> Given it's a Lenovo device and there are some drivers here, maybe it's
> also
> some know interface/structure, but I guess Hans would know more about
> that than
> I do.
>
> Best regards,
> Max

Hi,

it seems that the VPC0 ACPI device is handled by the already mentioned ideapad-laptop driver,
you probably just have to add the necessary event codes to ideapad_keymap[].

Armin Wolf