CUSBKeyboardDevice does not expose the CKeyboardBehaviour class or functions

[ArnoldUK]

I'm playing around with the 08-usbkeyboard sample which is working fine. I was also wanting to use the features of the CKeyboardBehaviour class as it has more capable and useful functions for handling the keyboard. In particular the KeyPressed, KeyReleased and GenerateEvent functions.

If the callback functions for the Key handlers set by the CUSBKeyboardDevice which are then registered with the CKeyboardBehaviour class, why is it not possible to access the CKeyboardBehaviour interface from the CUSBKeyboardDevice instance ? What is the correct way to use an instance of the CKeyboardBehaviour class ?

The CKeyboardBehaviour class does not have a constructor to pass the CUSBHIDDevice.
So I can't use code like this:

CUSBKeyboardDevice  * volatile pKeyboard;
pKeyboard = (CUSBKeyboardDevice *)pDeviceNameService->GetDevice("ukbd1", FALSE);
if (pKeyboard == 0) return false;

If the CUSBKeyboardDevice exposed the CKeyboardBehaviour m_Behaviour; member as public and static then it would make more sense to me to have access to those class functions, instead of creating another instance of the CKeyboardBehaviour class.

Thanks.

[rsta2]

The USB keyboard driver supports a cooked mode with escape sequences and a raw mode, which provides the raw USB keyboard codes and modifier key info. There is no way to access the CKeyboardBehaviour member of the driver directly, because it is intended for internal implementation purpose only.

[ArnoldUK]

I see how the USB Keyboard driver class works, but I'm not quite sure why the CKeyboardBehaviour has the redundant KeyPressed, KeyReleased and GenerateEvent. I cannot find anywhere within the Circle SDK where these functions are used by any other class, not even within the CUSBKeyboardDevice class. Also the CUSBKeyboardDevice::ReportHandler function appears to be redundant.

However, I do see the CKeyboardBehaviour class as a useful template to add to a project and use it alongside the CUSBKeyboardDevice driver like so:

CUSBKeyboardDevice  * volatile pKeyboard;
pKeyboard = (CUSBKeyboardDevice *)pDeviceNameService->GetDevice("ukbd1", FALSE);
if (pKeyboard == 0) return false;

pKeyboard->Configure(); //DOES THIS NEED TO BE CALLED ???

pKeyboard->RegisterRemovedHandler(MyKeyboardRemovedHandler);
pKeyboard->RegisterKeyStatusHandlerRaw(MyKeyStatusHandlerRaw);
pKeyboard->RegisterShutdownHandler(MyShutdownHandler);
pKeyboard->RegisterKeyPressedHandler(MyKeyPressedHandler);

CKeyboardBehaviour m_Behaviour;
m_Behaviour.RegisterKeyPressedHandler (MyKeyPressedHandler);
m_Behaviour.RegisterShutdownHandler (MyShutdownHandler);
m_Behaviour.RegisterSelectConsoleHandler (MySelectConsoleHandler);

//I can then use the CKeyboardBehaviour function calls which are not exposed in CUSBKeyboardDevice:
m_Behaviour.GenerateKeyEvent(ucKeyCode);
m_Behaviour.KeyPressed(ucKeyCode);
m_Behaviour.KeyReleased(ucKeyCode);

My point was that it seems unnecessary creating another instance of CKeyboardBehaviour when this class is created and used within the CUSBKeyboardDevice but is private and inaccessible. I'm not an expert here, but I'm sure you can correct me.

[rsta2]

Believe me, the class CKeyboardBehaviour will not help you. It implements the functions, needed internally by the USB keyboard driver in cooked mode. You could use the raw keyboard mode and use CKeyboardBehaviour to implement the cooked mode again by yourself. But why should you do this, because it is already provided by the USB keyboard driver (class CUSBKeyboardDevice).

sample/08-keyboard shows, how the keyboard cooked mode and alternatively the raw mode will be activated and used. CUSBKeyboardDevice::Configure() is called internally in the USB stack and must not be called by the application. Please also have a look into the docs.

BTW. These methods are not redundant. They are called by CUSBKeyboardDevice (KeyPressed(), KeyReleased(), inside CKeyboardBehaviour itself (GenerateEvent()) or by the base class CUSBHIDDevice (ReportHandler()).

[ArnoldUK]

I was wanting to use the CKeyboardBehaviour.KeyReleased function but that is not exposed by the CUSBKeyboardDevice.
Only registers for KeyPressed are exposed for registering your own handler to these functions.

How is it possible to register a KeyReleased handler in a similar fashion to KeyPressed ? I know I can add my own code for detecting when a key was last pressed and then released. But I thought it would useful for the CUSBKeyboardDevice class to also have a KeyReleased event handler. I hope this makes more sense.

[rsta2]

OK, if you need the key-released info, you have to use the raw mode of the USB keyboard driver. I think, this is, what most emulator developers do. Perhaps you can re-use some code from the Circle keyboard classes for your purpose, but you have to modify it.

[ArnoldUK]

Thanks @rsta2 that is what I have ended up doing and the raw handler sends 0 for parameters when all keys are released.
Only issue now is a possible bug with the key repeat functions. I have set the #define REPEAT_ENABLE in the keyboardbehaviour.cpp file and re-compiled circle but the key repeat does not work. I'm usung the raw capture handler. If I set the mixedmode to TRUE then my kernel freezes halfway through booting when initializing the USB keyboard device. There are no error messages either. mixedmode set to FALSE works fine but without key repeat functionality.

I will upload a sample of my keyboard testing kernel, maybe you can spot something out of place.
Appreciate your time and patience.

[rsta2]

You are welcome. Please note that the keyboard repeat function only works in cooked mode. There is no repeat in raw mode. There have also been issues with keyboard repeat. Sometimes the repeat did not stop. That's why it is not enabled by default. But I've tested it here again with sample/08-usbkeyboard (also in mixed mode) on a RPi 4 and it worked all right.

[ArnoldUK]

Ok, I'm using a Rpi 1 Model B for build and test. I'm sure I could easily code my own key repeat methods. I think some of my issues may have been casued by not having USE_USB_SOF_INTR set in sysconfig.h.
Cheers for the tips.

[ArnoldUK]

I've managed to sort out all the keyboard issues by changing the mixedmode boolean parameter in functionpKeyboard->RegisterKeyStatusHandlerRaw(m_pKeyStatusHandlerRaw, TRUE); to TRUE.

Key repeats work perfectly now in the cooked handler and I can also capture the modifer keys in the raw mode handler.
I should read the docs more often as the mixed mode operation was explained in the docs, I didn't understand the modes fully but now I have a much better understanding.