KDM fails to start(我遇到这个问题的时候没找到这个东西，改用slim 启动，现摘录如下，正确于否，待证)

KDM fails to start(http://www.gentoo.org/proj/en/desktop/kde/kde4-guide.xml)

Start by checking the permissions in /usr/share/config and if you're using +kdeprefix in$(kde4-config -prefix)/share/config. If they're 700, you need to update them to 755.Check previous section.If that doesn't solve the error, check the following notice in the kdm ebuild:

Code Listing 4.2: kdm notice

If when you restart xdm, kdm fails to start with a message like "gentoo kdm[2116]: X
server startup timeout, terminating" in /var/log/messages, uncomment the ServerTimeout
line in "grep kdmrc /var/db/pkg/kde-base/kdm-4.2.0/CONTENTS | cut -f2 -d " ""
and be sure to increase the timeout - 60 should work

Also be sure that the following services are started:

Code Listing 4.3: checking and starting services

# /etc/init.d/dbus status
# /etc/init.d/hald status
# /etc/init.d/consolekit status

If not, enable them by replacing status with start, and usethe command rc-update add dbus default for every oneof them to add them to default runlevel.

Finally, KDM could fail due to errors in xorg.conf. Take alook in logs: /var/log/Xorg.0.log and/var/log/kdm.log and fix xorg.conf accordingly.For additional help you can find us in IRC (#gentoo-kde at Freenode).