Unless otherwise specified, hotplug only sends a few important messages to syslog. To obtain more information, set HOTPLUG_DEBUG=yes. If you set this variable to the value max, every shell command is logged for all hotplug scripts. This means that /var/log/messages in which syslog stores all the messages will be much larger. As syslog is not launched during the boot process until after hotplug and coldplug, it is possible, however, for the first messages not to be logged. If these messages are important to you, specify a different log file via the variable HOTPLUG_SYSLOG. Information about this topic is contained in /etc/sysconfig/hotplug.
If a computer hangs during the boot process, disable hotplug or coldplug by entering NOHOTPLUG=yes or NOCOLDPLUG=yes, respectively, at the boot prompt. When the system is up and running, reenable hotplug by entering the command rchotplug start.
To find out whether a particular module loaded by hotplug is responsible for the problem, enter HOTPLUG_TRACE=<N> at the boot prompt. The names of all the modules are then output one after another on the screen until after N seconds they are actually loaded. You cannot intervene while this is going on.