Index: udev-config/doc/55-lfs.txt
===================================================================
--- udev-config/doc/55-lfs.txt	(revision 1c4800743d22d675ccfa48364d8aa558e8b7407c)
+++ udev-config/doc/55-lfs.txt	(revision 3cf57d40591f302edea1962a8949fe646b365b5c)
@@ -1,93 +1,19 @@
 Purpose of rules file:
 
-This is the core rules file for Udev on LFS.  If these rules were not included,
-most devices would either only work for root, or would not work at all.
-
+Most of the rules installed by Udev itself create devices with the correct
+properties.  This file contains rules that have not been merged upstream yet.
 
 Description of rules:
 
-By default, Udev creates device nodes with UID 0, GID 0, and permissions 0660,
-and in one flat directory structure with all nodes in /dev.  This does not
-always work well.
+By default, Udev creates device nodes with UID 0, GID 0, and permissions 0660.
 
-KERNEL=="ptmx"
+ISDN-related devices should be owned by the 'dialout' group, hence the following
+rule (and similar):
 
-Any uevent generated by the kernel with a name matching "ptmx" will match this
-rule.  Note that the matching done by Udev is shell-style; these are not regex
-matches.  For the ptmx device, we first change the permisions, by assigning to
-the MODE value:
+KERNEL=="ippp[0-9]*", GROUP="dialout"
 
-KERNEL=="ptmx", MODE="0666"
-
-We also assign a different GID to /dev/ptmx (also all other TTY devices), by
-assigning to the GROUP value:
-
-KERNEL=="ptmx", MODE="0666", "GROUP="tty"
-
-
-There are also devices that should not be in /dev, because historically they
-have been created in subdirectories instead.  For instance, all Alsa devices
-have traditionally been put into the /dev/snd subdirectory:
-
-KERNEL=="controlC[0-9]*", <...>, NAME="snd/%k"
-
-"%k" expands into "the original value of KERNEL" (note: not the pattern that was
-matched against).  This type of rule puts any matching device into the snd/
-subdirectory.
-
-Sometimes we need to move devices based on more than just their name.  For
-example, USB printer devices need to be moved to /dev/usb/lpX, but we can't
-match only "lp[0-9]*", because that would also match parallel port printers.
-So we match both KERNEL and SUBSYSTEMS in this case, to move USB printers only.
-
-
-Some devices also commonly have symlinks pointing to them -- for example,
-/dev/mouse is usually a symlink to /dev/input/mice.  We acheive this by
-assigning to the SYMLINK value.  But note that SYMLINK can store multiple values
-(because each device node could have multiple symlinks pointing to it), so we
-need to add to the list of symlinks, not overwrite the whole list:
-
-KERNEL=="mice", <...>, SYMLINK+="mouse"
-
-If we needed to add multiple symlinks, they would be space-separated inside the
-double quotes.
-
-Of course, symlinks, permissions, and device names can all be combined in a
-rule if needed.  But note that if you combine permissions and symlinks, or if
-you combine GROUP and symlinks, the permissions of the symlink will not be
-modified, only those of the target device.  (This is because the kernel does
-not pay any attention to the permissions on symlinks, only the permissions on
-their targets, and there's no reason to change something that won't be used.)
-
-
-Finally, we have this rule:
-
-SUBSYSTEM=="usb_device", PROGRAM="/bin/sh -c 'X=%k; X=$${X#usbdev}; B=$${X%%%%.*} D=$${X#*.}; echo bus/usb/$$B/$$D'", NAME="%c"
-
-This rule matches any device under the SUBSYSTEM of usb_device.  (All devices
-that were traditionally created under /proc/bus/usb/ use this subsystem.)  We
-tell Udev to run the specified PROGRAM; Udev will save the output of this
-program (it will be available under %c later).
-
-The program itself is a shell that starts by setting the variable X to the
-original kernel name (which is "usbdevB.D" for these devices, where B and D are
-the bus and device numbers of the USB device).  Then, the rule re-sets X to the
-value of X with the string "usbdev" removed from the start.  So now, X has the
-value "B.D".  Then, the rule sets B to the value of X after a period, and all
-characters following it, have been removed from the end; this sets B to just
-the string "B" (just the bus number of the USB device).  Then, the rule sets D
-to the value of X after a period, and all characters before it, have been
-removed from the beginning; this sets D to just the string "D" (just the device
-number).
-
-Then, the rule echoes "bus/usb/$B/$D" (bus/usb/bus-number/device-number), so
-Udev will capture that value.  The rule sets NAME="%c" to put the device node
-at /dev/bus/usb/bus-number/device-number.  (This is the same layout that the
-/proc/bus/usb/ devices used.)
-
-Most of the doubled characters in this rule are doubled so that Udev does not
-interpret them.  The rule looks all the more confusing because of this method
-of escaping special characters.
-
+The RTC-related rules cause the setclock bootscript to be run as soon as the
+RTC device has been created by Udev, meaning that times in log files, for
+example, are as accurate as possible as quickly as possible.
 
 A final word of caution: Any particular rule must be written on one line, and a
