gdm (or perhaps gdmgreeter) won't start after Red Hat upgrade from ELv3 to ELv4

Tue Sep 28 23:14:35 UTC 2010

I was running Red Hat ELv3 and I upgraded to v4 since v3 is going unsupported.
The upgrade ends by rebooting the machine and now the X11 login screen won't
start.  Apparently the gdmgreeter is failing.  The primary visible symptom is
that as the boot sequence completes the text login appears, then the screen
goes from black to a muted background with circling dots in the center, which
is what would normally be followed by the login screen.  Then it flashes, the
text login prompt reappers, and shortly thereafter the screen changes and gets 
circling dots again.

If I log in to the machine using the text (non-graphic) login I can "startx" 
and everything works just fine.  I can run the system-config-display utility 
and I've tried various screen size and depth variations.  There are no obvious 
error messages in /var/log/Xorg.0.log when using startx and none when gdm is 
trying to start.  The X11 server itself is apparently starting quite happily.

What is logged in /var/log/messages is just:
-----------------------------------
Sep 28 15:02:07 mica gdm[4447]: The display server has been shut down about 6
times in the last 90 seconds, it is likely that something bad is going on.  I
will wait for 2 minutes before trying again on display :0.
Sep 28 15:04:07 mica udevd[1127]: udev done!
Sep 28 15:04:14 mica last message repeated 5 times
Sep 28 15:04:16 mica gdm[12013]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 15:04:16 mica gdm[12013]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 15:04:16 mica gdm[12013]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 15:04:16 mica udevd[1127]: udev done!
Sep 28 15:04:18 mica last message repeated 2 times
Sep 28 15:04:20 mica gdm[12150]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 15:04:20 mica gdm[12150]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 15:04:20 mica gdm[12150]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 15:04:20 mica udevd[1127]: udev done!
Sep 28 15:04:25 mica udevd[1127]: udev done!
Sep 28 15:04:27 mica gdm[12291]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 15:04:27 mica gdm[12291]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 15:04:27 mica gdm[12291]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 15:04:27 mica udevd[1127]: udev done!
Sep 28 15:04:37 mica last message repeated 2 times
Sep 28 15:04:38 mica gdm[12430]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 15:04:39 mica gdm[12430]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 15:04:39 mica gdm[12430]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 15:04:39 mica udevd[1127]: udev done!
Sep 28 15:05:05 mica last message repeated 6 times
Sep 28 15:06:34 mica gdm[4447]: The display server has been shut down about 6
times in the last 90 seconds, it is likely that something bad is going on.  I
will wait for 2 minutes before trying again on display :0.
------------------------------------

If I enable debugging in gdm.conf then there is more information written to
the system log but there is no indication of what is actually going wrong.

-------------------------------------
Sep 28 14:46:00 mica gdm[4447]: gdm_main: Here we go...
Sep 28 14:46:01 mica gdm[4447]: gdm_start_first_unborn_local: Starting :0
Sep 28 14:46:01 mica gdm[4447]: gdm_display_manage: Managing :0
Sep 28 14:46:01 mica gdm[4447]: loop check: last_start 0, last_loop 0, now:
1285710361, retry_count: 0
Sep 28 14:46:01 mica gdm[4447]: Resetting counts for loop of death detection
Sep 28 14:46:01 mica gdm[4950]: gdm_slave_start: Starting slave process for :0
Sep 28 14:46:01 mica gdm[4950]: gdm_slave_start: Loop Thingie
Sep 28 14:46:01 mica gdm[4950]: Sending VT_NUM == -1 for slave 4950
Sep 28 14:46:01 mica gdm[4950]: Sending VT_NUM 4950 -1
Sep 28 14:46:01 mica gdm[4447]: gdm_display_manage: Forked slave: 4950
Sep 28 14:46:01 mica gdm[4447]: Handling message: 'VT_NUM 4950 -1'
Sep 28 14:46:01 mica gdm[4447]: Got VT_NUM == -1
Sep 28 14:46:01 mica gdm[4950]: gdm_server_start: :0
Sep 28 14:46:01 mica gdm[4950]: gdm_auth_secure_display: Setting up access for :0
Sep 28 14:46:01 mica gdm[4447]: (child 4950) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:01 mica gdm[4950]: gdm_auth_secure_display: Setting up access
Sep 28 14:46:01 mica gdm[4950]: gdm_auth_secure_display: Setting up access for
:0 - 1 entries
Sep 28 14:46:01 mica gdm[4950]: Sending COOKIE == <secret> for slave 4950
Sep 28 14:46:01 mica gdm[4950]: Sending COOKIE 4950 42...
Sep 28 14:46:01 mica gdm[4447]: Handling message: 'COOKIE 4950 42...'
Sep 28 14:46:01 mica fstab-sync[4992]: added mount point /media/floppy for
/dev/fd0
Sep 28 14:46:01 mica gdm[4447]: Got COOKIE == <secret>
Sep 28 14:46:01 mica gdm[4950]: gdm_server_spawn: Forked server on pid 5015
Sep 28 14:46:01 mica gdm[5015]: gdm_server_spawn: '/usr/X11R6/bin/X :0 -audit
0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7'
Sep 28 14:46:02 mica gdm[4950]: do_server_wait: Before mainloop waiting for server
Sep 28 14:46:02 mica udevd[1127]: udev done!
Sep 28 14:46:02 mica gdm[4447]: (child 4950) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:02 mica gdm[4950]: gdm_server_start: After mainloop waiting for
server
Sep 28 14:46:02 mica gdm[4950]: gdm_server_start: Completed :0!
Sep 28 14:46:02 mica gdm[4950]: Sending VT_NUM == 7 for slave 4950
Sep 28 14:46:02 mica gdm[4950]: Sending VT_NUM 4950 7
Sep 28 14:46:02 mica gdm[4447]: (child 4950) gdm_server_usr1_handler: Got
SIGUSR1, server running
Sep 28 14:46:02 mica gdm[4447]: Handling message: 'VT_NUM 4950 7'
Sep 28 14:46:02 mica udevd[1127]: udev done!
Sep 28 14:46:02 mica gdm[4447]: Got VT_NUM == 7
Sep 28 14:46:03 mica gdm[4950]: Sending XPID == 5015 for slave 4950
Sep 28 14:46:03 mica gdm[4447]: (child 4950) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:03 mica gdm[4950]: Sending XPID 4950 5015
Sep 28 14:46:03 mica gdm[4447]: Handling message: 'XPID 4950 5015'
Sep 28 14:46:03 mica gdm[4447]: Got XPID == 5015
Sep 28 14:46:03 mica gdm[4950]: gdm_slave_run: Opening display :0
Sep 28 14:46:03 mica gdm[4447]: (child 4950) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:04 mica udevd[1127]: udev done!
Sep 28 14:46:10 mica gdm[4950]: Sending START_NEXT_LOCAL
Sep 28 14:46:10 mica gdm[4447]: Handling message: 'START_NEXT_LOCAL'
Sep 28 14:46:10 mica gdm[4950]: gdm_slave_greeter: Running greeter on :0
Sep 28 14:46:11 mica gdm[4950]: gdm_slave_greeter: Greeter on pid 5119
Sep 28 14:46:11 mica gdm[4950]: Sending GREETPID == 5119 for slave 4950
Sep 28 14:46:11 mica gdm[4950]: Sending GREETPID 4950 5119
Sep 28 14:46:11 mica gdm[4447]: (child 4950) gdm_slave_child_handler
Sep 28 14:46:11 mica gdm[4447]: Handling message: 'GREETPID 4950 5119'
Sep 28 14:46:11 mica gdm[4447]: Got GREETPID == 5119
Sep 28 14:46:11 mica gdm[4447]: (child 4950) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:12 mica gdm[4950]: gdm_slave_wait_for_login: In loop
Sep 28 14:46:12 mica gdm[4950]: term_quit: Final cleanup
Sep 28 14:46:12 mica gdm[4950]: gdm_slave_quick_exit: Will kill everything
from the display
Sep 28 14:46:12 mica gdm[4950]: Running gdm_verify_cleanup and pamh != NULL
Sep 28 14:46:12 mica gdm[4447]: (child 4950) gdm_slave_child_handler
Sep 28 14:46:12 mica gdm[4447]: (child 4950) gdm_slave_child_handler: 5119 died
Sep 28 14:46:12 mica gdm[4447]: (child 4950) gdm_slave_child_handler: 5119
died of 6
Sep 28 14:46:12 mica gdm[4950]: gdm_server_stop: Server for :0 going down!
Sep 28 14:46:12 mica gdm[4950]: gdm_server_stop: Killing server pid 5015
Sep 28 14:46:12 mica gdm[4950]: gdm_server_stop: Server pid 5015 dead
Sep 28 14:46:12 mica gdm[4950]: gdm_slave_quick_exit: Killed everything from
the display
Sep 28 14:46:12 mica gdm[4447]: mainloop_sig_callback: Got signal 17
Sep 28 14:46:12 mica gdm[4447]: gdm_cleanup_children: child 4950 returned 65
Sep 28 14:46:12 mica gdm[4447]: gdm_child_action: In remanage
Sep 28 14:46:12 mica gdm[4447]: gdm_display_manage: Managing :0
Sep 28 14:46:12 mica gdm[4447]: loop check: last_start 1285710361, last_loop
1285710361, now: 1285710372, retry_count: 1
Sep 28 14:46:12 mica udevd[1127]: udev done!
Sep 28 14:46:12 mica gdm[5142]: gdm_slave_start: Starting slave process for :0
Sep 28 14:46:12 mica gdm[4447]: gdm_display_manage: Forked slave: 5142
Sep 28 14:46:12 mica gdm[5142]: gdm_slave_start: Loop Thingie
Sep 28 14:46:12 mica gdm[5142]: gdm_slave_run: Sleeping 1 seconds before
server start
Sep 28 14:46:13 mica gdm[5142]: Sending VT_NUM == -1 for slave 5142
Sep 28 14:46:13 mica gdm[5142]: Sending VT_NUM 5142 -1
Sep 28 14:46:13 mica gdm[4447]: Handling message: 'VT_NUM 5142 -1'
Sep 28 14:46:13 mica gdm[4447]: Got VT_NUM == -1
Sep 28 14:46:13 mica gdm[5142]: gdm_server_start: :0
Sep 28 14:46:13 mica gdm[5142]: gdm_auth_secure_display: Setting up access for :0
Sep 28 14:46:13 mica gdm[5142]: gdm_auth_secure_display: Setting up access
Sep 28 14:46:13 mica gdm[5142]: gdm_auth_secure_display: Setting up access for
:0 - 1 entries
Sep 28 14:46:13 mica gdm[5142]: Sending COOKIE == <secret> for slave 5142
Sep 28 14:46:13 mica gdm[5142]: Sending COOKIE 5142 c5...
Sep 28 14:46:13 mica gdm[4447]: (child 5142) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:13 mica gdm[4447]: Handling message: 'COOKIE 5142 c5...'
Sep 28 14:46:13 mica gdm[4447]: Got COOKIE == <secret>
Sep 28 14:46:13 mica gdm[5164]: gdm_server_spawn: '/usr/X11R6/bin/X :0 -audit
0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7'
Sep 28 14:46:13 mica gdm[5142]: gdm_server_spawn: Forked server on pid 5164
Sep 28 14:46:13 mica gdm[4447]: (child 5142) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:13 mica gdm[5142]: do_server_wait: Before mainloop waiting for server
Sep 28 14:46:13 mica gdm[4447]: (child 5142) gdm_server_usr1_handler: Got
SIGUSR1, server running
Sep 28 14:46:13 mica gdm[5142]: gdm_server_start: After mainloop waiting for
server
Sep 28 14:46:13 mica gdm[5142]: gdm_server_start: Completed :0!
Sep 28 14:46:13 mica gdm[5142]: Sending VT_NUM == 7 for slave 5142
Sep 28 14:46:13 mica gdm[5142]: Sending VT_NUM 5142 7
Sep 28 14:46:13 mica gdm[4447]: Handling message: 'VT_NUM 5142 7'
Sep 28 14:46:13 mica gdm[4447]: Got VT_NUM == 7
Sep 28 14:46:13 mica gdm[4447]: (child 5142) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:13 mica gdm[5142]: Sending XPID == 5164 for slave 5142
Sep 28 14:46:13 mica gdm[5142]: Sending XPID 5142 5164
Sep 28 14:46:13 mica gdm[4447]: Handling message: 'XPID 5142 5164'
Sep 28 14:46:13 mica gdm[4447]: Got XPID == 5164
Sep 28 14:46:13 mica gdm[5142]: gdm_slave_run: Opening display :0
Sep 28 14:46:14 mica udevd[1127]: udev done!
Sep 28 14:46:14 mica gdm[4447]: (child 5142) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:15 mica gdm[5142]: Sending START_NEXT_LOCAL
Sep 28 14:46:15 mica gdm[4447]: Handling message: 'START_NEXT_LOCAL'
Sep 28 14:46:15 mica gdm[5142]: gdm_slave_greeter: Running greeter on :0
Sep 28 14:46:15 mica gdm[4447]: (child 5142) gdm_slave_child_handler
Sep 28 14:46:15 mica gdm[5142]: gdm_slave_greeter: Greeter on pid 5261
Sep 28 14:46:15 mica gdm[5142]: Sending GREETPID == 5261 for slave 5142
Sep 28 14:46:15 mica gdm[5142]: Sending GREETPID 5142 5261
Sep 28 14:46:15 mica gdm[4447]: Handling message: 'GREETPID 5142 5261'
Sep 28 14:46:15 mica gdm[4447]: Got GREETPID == 5261
Sep 28 14:46:15 mica gdm[4447]: (child 5142) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:16 mica gdm[5142]: gdm_slave_wait_for_login: In loop
Sep 28 14:46:16 mica gdm[5142]: term_quit: Final cleanup
Sep 28 14:46:16 mica gdm[5142]: gdm_slave_quick_exit: Will kill everything
from the display
Sep 28 14:46:16 mica gdm[5142]: Running gdm_verify_cleanup and pamh != NULL
Sep 28 14:46:16 mica gdm[5142]: gdm_server_stop: Server for :0 going down!
Sep 28 14:46:16 mica gdm[5142]: gdm_server_stop: Killing server pid 5164
Sep 28 14:46:16 mica gdm[4447]: (child 5142) gdm_slave_child_handler
Sep 28 14:46:16 mica gdm[4447]: (child 5142) gdm_slave_child_handler: 5261 died
Sep 28 14:46:16 mica gdm[4447]: (child 5142) gdm_slave_child_handler: 5261
died of 6
Sep 28 14:46:16 mica gdm[5142]: gdm_server_stop: Server pid 5164 dead
Sep 28 14:46:16 mica gdm[5142]: gdm_slave_quick_exit: Killed everything from
the display
Sep 28 14:46:16 mica gdm[4447]: mainloop_sig_callback: Got signal 17
Sep 28 14:46:16 mica gdm[4447]: gdm_cleanup_children: child 5142 returned 65
Sep 28 14:46:16 mica gdm[4447]: gdm_child_action: In remanage
Sep 28 14:46:16 mica gdm[4447]: gdm_display_manage: Managing :0
Sep 28 14:46:16 mica gdm[4447]: loop check: last_start 1285710372, last_loop
1285710361, now: 1285710376, retry_count: 2
Sep 28 14:46:16 mica gdm[4447]: gdm_display_manage: Forked slave: 5278
Sep 28 14:46:16 mica gdm[5278]: gdm_slave_start: Starting slave process for :0
Sep 28 14:46:16 mica gdm[5278]: gdm_slave_start: Loop Thingie
Sep 28 14:46:16 mica gdm[5278]: gdm_slave_run: Sleeping 1 seconds before
server start
Sep 28 14:46:16 mica udevd[1127]: udev done!
Sep 28 14:46:17 mica gdm[5278]: Sending VT_NUM == -1 for slave 5278
Sep 28 14:46:17 mica gdm[5278]: Sending VT_NUM 5278 -1
Sep 28 14:46:17 mica gdm[4447]: Handling message: 'VT_NUM 5278 -1'
Sep 28 14:46:17 mica gdm[4447]: Got VT_NUM == -1
Sep 28 14:46:17 mica gdm[5278]: gdm_server_start: :0
Sep 28 14:46:17 mica gdm[5278]: gdm_auth_secure_display: Setting up access for :0
Sep 28 14:46:17 mica gdm[5278]: gdm_auth_secure_display: Setting up access
Sep 28 14:46:17 mica gdm[5278]: gdm_auth_secure_display: Setting up access for
:0 - 1 entries
Sep 28 14:46:17 mica gdm[5278]: Sending COOKIE == <secret> for slave 5278
Sep 28 14:46:17 mica gdm[5278]: Sending COOKIE 5278 87...
Sep 28 14:46:17 mica gdm[4447]: (child 5278) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:17 mica gdm[4447]: Handling message: 'COOKIE 5278 87...'
Sep 28 14:46:17 mica gdm[4447]: Got COOKIE == <secret>
Sep 28 14:46:17 mica gdm[5278]: gdm_server_spawn: Forked server on pid 5303
Sep 28 14:46:17 mica gdm[5278]: do_server_wait: Before mainloop waiting for server
Sep 28 14:46:17 mica gdm[4447]: (child 5278) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:17 mica gdm[5303]: gdm_server_spawn: '/usr/X11R6/bin/X :0 -audit
0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7'
Sep 28 14:46:17 mica gdm[5278]: gdm_server_start: After mainloop waiting for
server
Sep 28 14:46:17 mica gdm[5278]: gdm_server_start: Completed :0!
Sep 28 14:46:17 mica gdm[5278]: Sending VT_NUM == 7 for slave 5278
Sep 28 14:46:17 mica gdm[5278]: Sending VT_NUM 5278 7
Sep 28 14:46:17 mica gdm[4447]: (child 5278) gdm_server_usr1_handler: Got
SIGUSR1, server running
Sep 28 14:46:17 mica gdm[4447]: Handling message: 'VT_NUM 5278 7'
Sep 28 14:46:17 mica gdm[4447]: Got VT_NUM == 7
Sep 28 14:46:17 mica gdm[5278]: Sending XPID == 5303 for slave 5278
Sep 28 14:46:17 mica gdm[5278]: Sending XPID 5278 5303
Sep 28 14:46:17 mica gdm[4447]: (child 5278) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:17 mica gdm[4447]: Handling message: 'XPID 5278 5303'
Sep 28 14:46:17 mica gdm[4447]: Got XPID == 5303
Sep 28 14:46:18 mica gdm[5278]: gdm_slave_run: Opening display :0
Sep 28 14:46:18 mica gdm[4447]: (child 5278) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:18 mica udevd[1127]: udev done!
Sep 28 14:46:20 mica gdm[5278]: Sending START_NEXT_LOCAL
Sep 28 14:46:20 mica gdm[4447]: Handling message: 'START_NEXT_LOCAL'
Sep 28 14:46:20 mica gdm[5278]: gdm_slave_greeter: Running greeter on :0
Sep 28 14:46:20 mica gdm[4447]: (child 5278) gdm_slave_child_handler
Sep 28 14:46:20 mica gdm[5278]: gdm_slave_greeter: Greeter on pid 5403
Sep 28 14:46:20 mica gdm[5278]: Sending GREETPID == 5403 for slave 5278
Sep 28 14:46:20 mica gdm[5278]: Sending GREETPID 5278 5403
Sep 28 14:46:20 mica gdm[4447]: Handling message: 'GREETPID 5278 5403'
Sep 28 14:46:20 mica gdm[4447]: Got GREETPID == 5403
Sep 28 14:46:20 mica gdm[4447]: (child 5278) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:24 mica gdm[5403]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 14:46:25 mica gdm[5403]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 14:46:25 mica gdm[5403]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 14:46:26 mica gdm[5278]: term_quit: Final cleanup
Sep 28 14:46:26 mica gdm[5278]: gdm_slave_quick_exit: Will kill everything
from the display
Sep 28 14:46:26 mica gdm[5278]: gdm_server_stop: Server for :0 going down!
Sep 28 14:46:26 mica gdm[5278]: gdm_server_stop: Killing server pid 5303
Sep 28 14:46:26 mica gdm[4447]: (child 5278) gdm_slave_child_handler
Sep 28 14:46:26 mica gdm[4447]: (child 5278) gdm_slave_child_handler: 5403 died
Sep 28 14:46:26 mica gdm[4447]: (child 5278) gdm_slave_child_handler: 5403
died of 6
Sep 28 14:46:26 mica gdm[5278]: gdm_server_stop: Server pid 5303 dead
Sep 28 14:46:26 mica gdm[5278]: gdm_slave_quick_exit: Killed everything from
the display
Sep 28 14:46:26 mica gdm[4447]: mainloop_sig_callback: Got signal 17
Sep 28 14:46:26 mica gdm[4447]: gdm_cleanup_children: child 5278 returned 65
Sep 28 14:46:26 mica gdm[4447]: gdm_child_action: In remanage
Sep 28 14:46:26 mica gdm[4447]: gdm_display_manage: Managing :0
Sep 28 14:46:26 mica gdm[4447]: loop check: last_start 1285710376, last_loop
1285710361, now: 1285710386, retry_count: 3
Sep 28 14:46:26 mica gdm[5427]: gdm_slave_start: Starting slave process for :0
Sep 28 14:46:26 mica gdm[5427]: gdm_slave_start: Loop Thingie
Sep 28 14:46:26 mica gdm[5427]: gdm_slave_run: Sleeping 1 seconds before
server start
Sep 28 14:46:26 mica gdm[4447]: gdm_display_manage: Forked slave: 5427
Sep 28 14:46:26 mica udevd[1127]: udev done!
Sep 28 14:46:27 mica gdm[5427]: Sending VT_NUM == -1 for slave 5427
Sep 28 14:46:27 mica gdm[5427]: Sending VT_NUM 5427 -1
Sep 28 14:46:27 mica gdm[4447]: Handling message: 'VT_NUM 5427 -1'
Sep 28 14:46:27 mica gdm[4447]: Got VT_NUM == -1
Sep 28 14:46:27 mica gdm[5427]: gdm_server_start: :0
Sep 28 14:46:27 mica gdm[5427]: gdm_auth_secure_display: Setting up access for :0
Sep 28 14:46:27 mica gdm[5427]: gdm_auth_secure_display: Setting up access
Sep 28 14:46:27 mica gdm[5427]: gdm_auth_secure_display: Setting up access for
:0 - 1 entries
Sep 28 14:46:27 mica gdm[5427]: Sending COOKIE == <secret> for slave 5427
Sep 28 14:46:27 mica gdm[5427]: Sending COOKIE 5427 3c...
Sep 28 14:46:27 mica gdm[4447]: (child 5427) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:27 mica gdm[4447]: Handling message: 'COOKIE 5427 3c...'
Sep 28 14:46:27 mica gdm[4447]: Got COOKIE == <secret>
Sep 28 14:46:27 mica gdm[5452]: gdm_server_spawn: '/usr/X11R6/bin/X :0 -audit
0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7'
Sep 28 14:46:27 mica udevd[1127]: udev done!
Sep 28 14:46:27 mica gdm[5427]: gdm_server_spawn: Forked server on pid 5452
Sep 28 14:46:27 mica gdm[5427]: gdm_server_start: Completed :0!
Sep 28 14:46:27 mica gdm[5427]: Sending VT_NUM == 7 for slave 5427
Sep 28 14:46:27 mica gdm[5427]: Sending VT_NUM 5427 7
Sep 28 14:46:27 mica gdm[4447]: (child 5427) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:27 mica gdm[4447]: (child 5427) gdm_server_usr1_handler: Got
SIGUSR1, server running
Sep 28 14:46:27 mica gdm[4447]: Handling message: 'VT_NUM 5427 7'
Sep 28 14:46:27 mica gdm[4447]: Got VT_NUM == 7
Sep 28 14:46:27 mica gdm[5427]: Sending XPID == 5452 for slave 5427
Sep 28 14:46:27 mica gdm[5427]: Sending XPID 5427 5452
Sep 28 14:46:28 mica udevd[1127]: udev done!
Sep 28 14:46:28 mica gdm[4447]: (child 5427) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:28 mica gdm[4447]: Handling message: 'XPID 5427 5452'
Sep 28 14:46:28 mica gdm[4447]: Got XPID == 5452
Sep 28 14:46:28 mica gdm[5427]: gdm_slave_run: Opening display :0
Sep 28 14:46:28 mica gdm[4447]: (child 5427) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:30 mica gdm[5427]: Sending START_NEXT_LOCAL
Sep 28 14:46:30 mica gdm[4447]: Handling message: 'START_NEXT_LOCAL'
Sep 28 14:46:30 mica gdm[5427]: gdm_slave_greeter: Running greeter on :0
Sep 28 14:46:30 mica gdm[4447]: (child 5427) gdm_slave_child_handler
Sep 28 14:46:30 mica gdm[5427]: gdm_slave_greeter: Greeter on pid 5549
Sep 28 14:46:30 mica gdm[5427]: Sending GREETPID == 5549 for slave 5427
Sep 28 14:46:30 mica gdm[5427]: Sending GREETPID 5427 5549
Sep 28 14:46:30 mica gdm[4447]: Handling message: 'GREETPID 5427 5549'
Sep 28 14:46:30 mica gdm[4447]: Got GREETPID == 5549
Sep 28 14:46:30 mica gdm[4447]: (child 5427) gdm_slave_usr2_handler: :0 got
USR2 signal
Sep 28 14:46:30 mica gdm[5549]: failsafe dialog failed (inhibitions: 0 0)
Sep 28 14:46:30 mica gdm[5549]: failsafe dialog failed (inhibitions: 0 1)
Sep 28 14:46:30 mica gdm[5549]: failsafe dialog failed (inhibitions: 1 1)
Sep 28 14:46:31 mica gdm[5427]: term_quit: Final cleanup
-------------------------------------

Does anyone know what this "failsafe dialog" is?  Or what "inhibitions" are? 
Is there perhaps a way to get gdmgreeter to log something useful?

Everything I've been able to find by way of Google is several years old and
usually hardware specific one way or another.

Any suggestions?

		 Gary