Input device design (3)

[Russell Shaw]

Johnson, Charles F wrote:
> Russell's comments is exactly what I've been thinking of:
> 
> **********************
> *      X Server      *
> **********************         *******************
> * X Config Interface *  <----  * X Config Client *  -> DBUS -> HAL
> **********************         *******************
> 
> In this setup, the X Config Client (XCC) would handle:
> 
> 1. Input Device Discovery
> 2. Input Device Hot Plug & Removal Tracking
> 3. Notifications to X Server on Events in #2
> 
> This enables:
> 1. Removal from the X server knowledge of OS & platform specific 
>    hot plug mechanisms.
>    (Linux can have its own, Solaris its own, etc.).
> 2. Makes it possible that the X server may not have to run as root 
>    anymore.  (Assuming the XCC passes a fd to the server.)
> 3. Allows the X server to evolve independent of the 
>    OS & platform configuration detection mechanism.
> 
> Please let me know if this is too simplistic view of the world.

Hi,
How about:
                                      System interface agents.
+----------+                       +----------------------------------------+
| X server |<--- /dev/Xinput  <--- | One or more X event generators         |
|          |---> /dev/Xoutput ---> |   and readers.                         |
+----------+                       | X events for mouse button presses      |
                                    |   and movement etc,                    |
                                    | X events for keypress, keyrelease etc, |
                                    | X events for hardware changes.         |
                                    | Requests from server to reset or query |
                                    |   hardware.                            |
                                    +----------------------------------------+

All the configuration and hardware knowledge can be taken out of the X server.
The server only knows keypress/release etc, and knows nothing about keycodes.

Changing a keyboard or mouse only causes a "hardware change" X event to be
written to the /dev/Xinput fifo for the X server to read and act upon if
neccessary, such as relaying the event to clients. The X server or clients
could respond with a "hardware query" event that gets written to /dev/Xoutput
for the system interface agents to respond to if neccessary.