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Table of Contents
getconfig - meta configuration files for getconfig(1)
*.cfg
getconfig is a programatic interface that is used by the XFree86
server to get configuration information about video hardware when operating
without an XF86Config file.
This implementation of getconfig is written
in perl. It processes rules from meta-configuration files. All meta-configuration
files have a .cfg suffix.
Lines starting with a pound-sign (#) are comments,
and are ignored. Blank lines that consist only of white space are also treated
as comments and ignored.
The first non-comment line must be a signature string
followed by the file format version number. The signature string is
"XFree86 Project getconfig rules file. Version: "
The currently defined version is "1.0". Files that do not have the correct
signature string are ignored.
The remaining non-comment lines define rules.
The start of a new rule is indicated by a line with no leading white space.
Subsequent lines making up a rule must be indented with white space. Logical
lines within a rule may be split over multiple physical lines by using
the usual continuation convention ('\' at the end of the line). The first
logical line of each rule is a perl expression. It may be any valid perl
expression whose evaluated (with 'eval') result may be used as the argument
to a perl 'if' statement. The second logical line should be the name of the
XFree86 video driver to use when the rule is true, and subsequent logical
lines of each rule, if present, are additional configuration output for
the video device's XF86Config Device section. The driver name and additional
lines of configuration information are written to standard output when
the rule is chosen as the successful rule.
Pseudo rules consisting of perl
expressions may be present in the file for the purpose of defining custom
perl variables or setting the weight to use for the following rules. Pseudo
rules are rules that consist of a single logical line only, and the are
never candidates themselves for the successful rule.
Several perl variables
are pre-defined, and may be used within rules. They include:
$vendor PCI vendor ID
$device PCI device ID
$revision PCI revision ID
$subsys PCI subsystem ID
$subsysVendor PCI subsystem vendor ID
$class PCI class
$XFree86Version XFree86 version, as a 'v' string
$XFree86VersionNumeric XFree86 numeric version
$XFree86VersionMajor XFree86 major version
$XFree86VersionMinor XFree86 minor version
$XFree86VersionPatch XFree86 patch version
$XFree86VersionSnap XFree86 snap version
$weight current rule weight
The $weight variable deterines the weight of the rules as they are processed.
The weight for subsequent rules may be set with a pseudo rule that sets
or changes the value of $weight. The default weight, and the weight used
for built-in rules is 500. The meta-configuration files are processed in
an unpredictable order. The weighting of the rules is used to determine
their relative priority
After processing all of the rules, both built-in
and those read from the meta-configration files, the getconfig program chooses
as the successful rule the last and highest weighted rule that evaluates
to true.
.cfg files located in the search path. The search path typically
specified by the XFree86 server is:
/etc/X11
/usr/X11R6/etc/X11
<modulepath>
/usr/X11R6/lib/X11/getconfig
where <modulepath> is the XFree86 server's module search path.
- /usr/X11R6/lib/X11/getconfig/xfree86.cfg
- Default rules file that gets installed. This file doesn't contain any rules
by default.
- /usr/X11R6/lib/X11/getconfig/cfg.sample
- A sample rules file that
gives some examples of what types of rules can appear in rules files.
getconfig(1)
, XFree86(1)
, XF86Config(5)
.
The XFree86 automatic
configuration support and the getconfig interface was written by David
H. Dawes, with the support of X-Oz Technologies.
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