Hang on splash logo while booting

[Peter Flynn]

On 08/11/17 05:41, Ralf Mardorf wrote:
 > Perhaps it was just a disk check and now it would boot with the splash
 > screen, too.

Sadly not...it is at least consistently failing :-)

 > On 08/11/17 07:30, Colin Law wrote:
[...]
> As Ralf suggests try again with splash. If that still doesn't work tell 
> us what you did to stop the splash. Also boot again without splash and 
> look in syslog to see what is there for the failed boot.

I haven't had time to look at syslog yet, and I'm away from the machine now.

A more accurate description:

1. Pressing Esc when the splash screen appears makes the display go
    blank and nothing more happens. Pressing keys does nothing, and there
    is no mouse cursor. Basically dead, although the lights are still on.

2. When it hangs, it can always be rebooted after power cycle using
    Recovery Mode from the Grub menu. It asks for the disk crypt in text
    mode, and continues to boot OK. Completing full boot from the menu
    gets a normal graphical login and everything works.

3. Removing 'quiet splash' from the Grub boot line goes to text-mode
    boot, but instead of the screen being a 24-line 80-char monochrome
    TTY, the font is smaller and it's in colour, like with a colour
    xterm. Boot goes on for 40 secs then hangs. As it's not
    copy/pastable, I wrote it down:

> Reached target multi-user system
> [*] Started WPA Supplicant
> [40.1000001] Watchdog: BUG: soft lockup - CPU#7 stuck for 23s! [gpu-manager:933]
> [***] A start job is running for Detect the available GPUs and deal with any system changes (3 min 47s/no limit)

That last line gets repeated every few minutes. I understand what it 
says, but it's obviously not able to report what the underlying problem 
is. A stuck CPU is doubleplusungood. Then it spews out a little more:

> [242.652679] Tainted: G L 4.13-0-16-generic #19-Ubuntu
> echo 0 > /proc/sys/kernel/hung_task_timeout_secs disables this message

Then it goes back to A start job is running, and the whole thing cycles.

Hold down power for 5 secs and force halt. Reboot from Recovery, select 
full reboot, and it's back in action. Normal shutdown, power off. Then 
power up and it enters graphical boot, give the disk crypt, and the 
Ubuntu logo white does start turning red until the third one, when it 
hangs solid.

Once it was booted I looked at dmesg but there was nothing in there 
about CPU#7 or any lockup, but that seems to have occurred after 
runlevel 5 was reached. I then did a system upgrade from 17.04 to 17.10, 
not something I normally do on my production systems, but in this case I 
now regard the laptop as sacrificial. This upgrade has not changed the 
behaviour, however: it still hangs in graphical boot as described.

It's of course possible that it is a hardware problem, I guess. But for 
the first 2-3 days of use (new last week) it worked fine, being 
installed with 17.04 without problems, and being shut down and rebooted 
several times. Then this problem occurred suddenly and without any event 
acting as warning.

///Peter