mmorris's questions

Disclaimer there are MANY questions on this topic and none of them apply to my situation.

Note the following:

1. The system previously ran Ubuntu 12.04 Desktop 32bit without issue.
2. This is a clean install, not an upgrade. Previous install was overwritten.
3. The black screen comes after logging in, not while booting.
4. The black screen comes regardless of the video driver, default(nouveau) or nvidia
5. It is not sporadic, it happens all the time.
6. It is not the result of returning from sleep or suspend.

I did a clean install of Ubuntu 14.04 Desktop 32bit (ubuntu-14.04-desktop-i386.iso) using liveUSB. The installation completes successfully, the system reboots, and I login. After logging in: the screen (with the background visible) flickers and eventually goes black (no background, no Unity Panel, no Unity Launcher), and I am able to move the mouse about the screen.

Just in case there is an update that resolves this, I switch to tty1 (Ctrl + Alt + F1) and type:

sudo apt-get update
sudo apt-get dist-upgrade

Reboot and same thing after logging in: the screen flickers and eventually goes black, and I am able to move the mouse about the screen.

The machine has nvidia graphics card, the GeForce FX 5700LE video card.

lspci | grep VGA

01:00.0 VGA compatible controller: NVIDIA Corporation NV36 [GeForce FX 5700LE] (rec a1)

So I install the nvidia 173 drivers:

sudo apt-get install nvidia-173

Reboot and now after logging in: the screen goes black, and I am able to move the mouse about the screen.

There are a number of post about Ubuntu 14.04 black screen after login, however they appear to be the result of upgrading from a previous version of Ubuntu and not a clean install. Regardless of that I tired the solution to that problem which is to purge the existing nvidia drivers via sudo apt-get remove --purge nvidia* . Not to my surprise after rebooting and logging in, I see the original behavior: the screen flickers and eventually goes black, and I am able to move the mouse about the screen.

I also tried to boot Ubuntu in recovery mode using failsafeX, I see a popup that says, "The System is running in low-graphics mode". No mouse is visible. I hit tab and enter. Next screen says, "What would you like to do?" and "Run in low-graphics mode for just one session" is selected. I hit tab twice, highlighting "OK" and hit enter. Next screen says, "Stand by one minute while the display restarts…". I hit enter. I see a shining black screen with no mouse.

I read that this is might be another issue since it occurs *after* entering your password on the login page.

I created a RAID with:

sudo mdadm --create --verbose /dev/md1 --level=mirror --raid-devices=2 /dev/sdb1 /dev/sdc1
sudo mdadm --create --verbose /dev/md2 --level=mirror --raid-devices=2 /dev/sdb2 /dev/sdc2

sudo mdadm --detail --scan returns:

ARRAY /dev/md1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

Which I appended it to /etc/mdadm/mdadm.conf, see below:

# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.
#DEVICE partitions containers

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays

# This file was auto-generated on Mon, 29 Oct 2012 16:06:12 -0500
# by mkconf $Id$
ARRAY /dev/md1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

cat /proc/mdstat returns:

Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] 
md2 : active raid1 sdb2[0] sdc2[1]
      208629632 blocks super 1.2 [2/2] [UU]

md1 : active raid1 sdb1[0] sdc1[1]
      767868736 blocks super 1.2 [2/2] [UU]

unused devices: <none>

ls -la /dev | grep md returns:

brw-rw----   1 root disk      9,   1 Oct 30 11:06 md1
brw-rw----   1 root disk      9,   2 Oct 30 11:06 md2

So I think all is good and I reboot.

After the reboot, /dev/md1 is now /dev/md126 and /dev/md2 is now /dev/md127?????

sudo mdadm --detail --scan returns:

ARRAY /dev/md/ion:1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md/ion:2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

cat /proc/mdstat returns:

Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] 
md126 : active raid1 sdc2[1] sdb2[0]
      208629632 blocks super 1.2 [2/2] [UU]

md127 : active (auto-read-only) raid1 sdb1[0] sdc1[1]
      767868736 blocks super 1.2 [2/2] [UU]

unused devices: <none>

ls -la /dev | grep md returns:

drwxr-xr-x   2 root root          80 Oct 30 11:18 md
brw-rw----   1 root disk      9, 126 Oct 30 11:18 md126
brw-rw----   1 root disk      9, 127 Oct 30 11:18 md127

All is not lost, I:

sudo mdadm --stop /dev/md126
sudo mdadm --stop /dev/md127
sudo mdadm --assemble --verbose /dev/md1 /dev/sdb1 /dev/sdc1
sudo mdadm --assemble --verbose /dev/md2 /dev/sdb2 /dev/sdc2

and verify everything:

sudo mdadm --detail --scan returns:

ARRAY /dev/md1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

cat /proc/mdstat returns:

Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] 
md2 : active raid1 sdb2[0] sdc2[1]
      208629632 blocks super 1.2 [2/2] [UU]

md1 : active raid1 sdb1[0] sdc1[1]
      767868736 blocks super 1.2 [2/2] [UU]

unused devices: <none>

ls -la /dev | grep md returns:

brw-rw----   1 root disk      9,   1 Oct 30 11:26 md1
brw-rw----   1 root disk      9,   2 Oct 30 11:26 md2

So once again, I think all is good and I reboot.

Again, after the reboot, /dev/md1 is /dev/md126 and /dev/md2 is /dev/md127?????

sudo mdadm --detail --scan returns:

ARRAY /dev/md/ion:1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md/ion:2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

cat /proc/mdstat returns:

Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] 
md126 : active raid1 sdc2[1] sdb2[0]
      208629632 blocks super 1.2 [2/2] [UU]

md127 : active (auto-read-only) raid1 sdb1[0] sdc1[1]
      767868736 blocks super 1.2 [2/2] [UU]

unused devices: <none>

ls -la /dev | grep md returns:

drwxr-xr-x   2 root root          80 Oct 30 11:42 md
brw-rw----   1 root disk      9, 126 Oct 30 11:42 md126
brw-rw----   1 root disk      9, 127 Oct 30 11:42 md127

What am I missing here?

In Ubuntu 10.04 while at the login screen (gdm), when the computer's physical power button was pressed a screen popped up that offered options on shutting down the system (shutdown, restart, cancel, ...) along with a 60 second countdown that when elapsed would shutdown the computer.

This is useful if you have a system that you use mainly as a server and occasionally as a desktop. When used as a server, one could press the computer's physical power button and 60 seconds later the system powered down,

Is there a way turn this behavior on or emulate it in lightdm? Or is it a bug ACPI events to shutdown/reboot don't generate a popup like after logging in?

I found a work around, Use PC's power button while screen is locked. However this is more heavy handed that what I am looking for. It shuts down the system immediately after the computer's physical power button is pressed in all cases, logged in or not. It also does not give the option to abort the pending shutdown in the case the computer's power button was pressed accidentally.