QDBusConnection doesn't awake a slot

[MT13]

so I found the same problem here: http://qt-project.org/forums/viewthread/52203 but the solution didn't work for me. My qdbusconnection returns that it is connected, but doesn't awake a slot.

here is the code:
@void connectToDesktop()
{
if (QDBusConnection::sessionBus().isConnected())
{
bool res = QDBusConnection::sessionBus().connect("org.kde.Solid.PowerManagement",
"/org/kde/Solid/PowerManagement/Actions/BrightnessControl",
"org.kde.Solid.PowerManagement.Actions.BrightnessControl",
"brightnessChanged",
this,
SLOT(myFn()));
}
if(res==true)
{
Log()<<"connectToDesktop: --- connected!\n";
}

if (res==false)
{
Log() << "connection to desktop failed.\n";
return;
}
}

void myFn()
{
Log()<<"myFn: --- in myFn\n";
}
@

so, my program gets into the if(res==true) scope and prints that it is connected, but doesn't print log in myFn.

This code is a part of a bigger one, so QApplication is included and used elsewhere. Can someone help me? Thanks...

Edited:

I understood what was wrong. My application runs from root that's why dbus doesn't awake a slot. When I run the same code in the different project, which runs as usual user, it works.

But now I don't know how to make it work from root...

[SGaist]

Hi and welcome to devnet,

If I understood the doc correctly your slot signature doesn't match the brightnessChanged signature. That's why it doesn't work. myFn should be myFn(int)

[MT13]

Hello an thank you :)

I did what you said, but it still doesn't work =(

I also tried different services, but it does the same: returns true, but doesn't awake the slot.

[SGaist]

You should check that you currently have the service registered with

@QDBusConnection::sessionBus().interface()->isServiceRegistered("org.kde.Solid.PowerManagement")@