This scan code set is more advanced than the basic scan code set 1, and
is required to be supported for some bare metal hardware that might not
properly enable the PS2 first port translation in the i8042 controller.
LibWeb can now also generate bindings for keyboard events like the Pause
key, as well as other function keys (such as Right Alt, etc).
The logic for handling scan code sets is implemented by the PS2 keyboard
driver and is abstracted from the main HID KeyboardDevice code which
only handles "standard" KeyEvent(s).
This scan code set is more advanced than the basic scan code set 1, and
is required to be supported for some bare metal hardware that might not
properly enable the PS2 first port translation in the i8042 controller.
LibWeb can now also generate bindings for keyboard events like the Pause
key, as well as other function keys (such as Right Alt, etc).
The logic for handling scan code sets is implemented by the PS2 keyboard
driver and is abstracted from the main HID KeyboardDevice code which
only handles "standard" KeyEvent(s).
For a very long time, the kernel had only support for basic PS/2 devices
such as the PS2 AT keyboard and regular PS2 mouse (with a scroll wheel).
To adapt to this, we had very simple abstractions in place, essentially,
the PS2 devices were registered as IRQ handlers (IRQ 1 and 12), and when
an interrupt was triggered, we simply had to tell the I8042Controller to
fetch a byte for us, then send it back to the appropriate device for
further processing and queueing of either a key event, or a mouse packet
so userspace can do something meaningful about it.
When we added the VMWare mouse integration feature it was easily adapted
to this paradigm, requiring small changes across the handling code for
these devices.
This patch is a major cleanup for any future advancements in the HID
subsystem.
It ensures we do things in a much more sane manner:
- We stop using LockRefPtrs. Currently, after the initialization of the
i8042 controller, we never have to change RefPtrs in that class, as we
simply don't support PS2 hotplugging currently.
Also, we remove the unnecessary getters for keyboard and mouse devices
which also returned a LockRefPtr.
- There's a clear separation between PS2 devices and the actual device
nodes that normally exist in /dev. PS2 devices are not polled, because
when the user uses these devices, they will trigger an IRQ which when
is handled, could produce either a MousePacket or KeyEvent, depending
on the device state.
The separation is crucial for buses that are polled, for example - USB
is a polled bus and will not generate an IRQ for HID devices.
- There's a clear separation in roles of each structure. The PS2 devices
which are attached to a I8042Controller object are managing the device
state, while the generic MouseDevice and KeyboardDevice manage all
related tasks of a CharacterDevice, as well as interpreting scan code
events and mouse relative/absolute coordinates.
