Input device design (3)

Johnson, Charles F charles.f.johnson at
Mon Aug 29 15:01:56 PDT 2005

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.

--Charles Johnson
Intel Corp.
charles.f.johnson at

>-----Original Message-----
>From: xorg-bounces at [mailto:xorg-
>bounces at] On Behalf Of Russell Shaw
>Sent: Monday, August 29, 2005 9:45 AM
>To: Discuss issues related to the xorg tree
>Subject: Re: Input device design (3)
>Joe Krahn wrote:
>> I have over the last several years made efforts to work with XInput
>All this has got me thinking a bit. It is desireable to try and keep
>hardware specifics and policy out of the X server.
>I've disregarded my previous ideas. Now i thinK:
>   The X server could monitor a special device such as /dev/sysconfig
>   a known ip address or socket so that if the user was to unplug/plug
>   mice, keyboards, or any other hardware, the kernel or user-space
>   programs or a daemon could write notification messages to it.
>When any of these server parameters/properties is changed, an X event
>can be sent to all the running clients so they can adapt.
>So to implement this:
>   1) define a message protocol for the X server to read hardware
>      from the device or socket. Maybe dbus could be used, but i'm not
>      with it
>   2) add some new X message protocols such as "hardware changed"
>The actual programs for configuring hardware don't need to know about
>they or the kernel or a daemon needs to write the notification to the
>that the X server is listening to.
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>xorg at

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