The HAL replacement plans

Alan Coopersmith Alan.Coopersmith at Sun.COM
Wed Dec 2 11:01:13 PST 2009


I got tired of typing the same answer into IRC every few days so
I typed it into the wiki so we can just paste the URL in to answer
future questions on IRC & e-mail:

	http://www.x.org/wiki/XorgHAL

If you see anything that needs to be corrected, expanded, better
explained, etc. please use the power of the wiki to fix it.

The current text (for those too lazy to look) is:

Versions that use HAL
---------------------

Xorg versions 1.4 through (at least) 1.7 use HAL for several things related to
input devices:

   1. Finding input devices at startup
   2. Being notified of input device hotplugging (arrival & removal)
   3. Mapping system input devices to Xorg input driver modules (via .fdi
      files provided with Xorg input drivers)
   4. Setting input device options (via user-customized .fdi files)

HAL is not used by Xorg for output devices or any other devices, only input.

Future Versions
---------------

Since the HAL project has stopped development and deprecated itself, X.Org is
planning to move off HAL in the future, though this work is still in
progress/planning, not yet delivered, so no dates/release schedule is yet known.

The currently planned replacements for the above functionality pieces are:

   1. Direct calls to OS-dependent device enumeration libraries (libudev on
      Linux, libdevinfo on Solaris, etc. - basically whatever HAL called to
      do this)
   2. Direct calls to OS-dependent device notification libraries (libudev on
      Linux, libsysevent on Solaris, etc. - basically whatever HAL called to
      do this)
   3. Input driver delivered files in a new xorg.conf.d directory that use
      new syntax for matching devices (see patches proposed on xorg-devel)
   4. User edited xorg.conf file.

-- 
	-Alan Coopersmith-           alan.coopersmith at sun.com
	 Sun Microsystems, Inc. - X Window System Engineering



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