Notifications about ACPI events in userspace?

[Florian Echtler <floe@xxxxxxxxxxxxxx>]

Hi everyone,

I'm currently adding support for the iMac's target display mode (TDM) to Linux.
When an external DisplayPort source is added/removed, the following ACPI code is
invoked:

    Scope (\_SB.PCI0.LPCB.SMC)
    {
        Device (DPPT)
        {
            Name (_HID, EisaId ("APP000C"))  // _HID: Hardware ID
            Name (_CID, "smc-dppt")  // _CID: Compatible ID
        }
    }

   Scope (\_SB.PCI0.LPCB.EC)
    {
        Method (_Q30, 0, NotSerialized)  // _Qxx: EC Query
        {
            Notify (\_SB.PCI0.LPCB.SMC.DPPT, 0x80) // Status Change
        }

        Method (_Q31, 0, NotSerialized)  // _Qxx: EC Query
        {
            Notify (\_SB.PCI0.LPCB.SMC.DPPT, 0x81) // Information Change
        }
    }


I've already verified that the method calls do indeed take place, by turning on
EC debugging. The APP000C device does also exist in /sys.

However, I'm not seeing anything happening with either acpi_listen or kacpimon.
Does this require any kernel changes, or could I subscribe to these events somehow?

Best, Florian
-- 
SENT FROM MY DEC VT50 TERMINAL

Attachment: signature.asc
Description: OpenPGP digital signature