Patch from John Wehle:

A side effect of opening the cdrom device on FreeBSD is it
locks the drive.  This makes cdio_get_media_changed less
useful and prevents you from being able to switch disks
when using things such as the audacious media player.

This patch simply unlocks the drive right after it's opened
prior to opening the cam passthrough device.

lib/driver/FreeBSD/freebsd_cam.c

@@ -1,7 +1,7 @@
 /*
   $Id: freebsd_cam.c,v 1.12 2008/04/21 18:30:20 karl Exp $
 
-  Copyright (C) 2004, 2005, 2008 Rocky Bernstein <rocky@gnu.org>
+  Copyright (C) 2004, 2005, 2008, 2009 Rocky Bernstein <rocky@gnu.org>
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -122,6 +122,8 @@ init_freebsd_cam (_img_private_t *p_env)
       return false;
     }
 
+  (void)ioctl(p_env->gen.fd, CDIOCALLOW);
+
   if (ioctl (p_env->gen.fd, CAMGETPASSTHRU, &p_env->ccb) < 0)
     {
       cdio_warn ("open: %s", strerror (errno));