Bug 94751

Summary:	Console output is broken on requesting hibernation
Product:	Power Management	Reporter:	sworddragon2
Component:	Hibernation/Suspend	Assignee:	Aaron Lu (aaron.lu)
Status:	CLOSED MOVED
Severity:	normal	CC:	aaron.lu
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	3.19.1	Subsystem:
Regression:	No	Bisected commit-id:

Description sworddragon2 2015-03-11 15:22:29 UTC

On executing "echo disk > /sys/power/state" the screen goes a few seconds black before the system does shutdown but on this black screen I'm seeing on the first line the upper half of the text "Begin: Loading essential drivers ... done." without the first letter (the B seems to be visible for a very short amount of time before it vanishes).

Comment 1 Aaron Lu 2015-03-13 02:53:53 UTC

Not a functional problem I suppose?
The text "Begin: Loading essential drivers ... done." seems to be what's left in somewhere of the GPU's buffer and on hibernation, it's displayed again.

The no_console_suspend kernel cmdline option may change this behavior.

Comment 2 sworddragon2 2015-03-14 21:12:54 UTC

(In reply to Aaron Lu from comment #1)
> Not a functional problem I suppose?

After hibernating and booting the system it does boot normally instead of loading the state from the hibernation file but currently I'm assuming it has something to do with my encrypted swap (dm-crypt) as I don't have configured something special which is maybe needed here.


(In reply to Aaron Lu from comment #1)
> The text "Begin: Loading essential drivers ... done." seems to be what's
> left in somewhere of the GPU's buffer and on hibernation, it's displayed
> again.

I'm always seeing this line at first on booting on the second console that appears.


(In reply to Aaron Lu from comment #1)
> The no_console_suspend kernel cmdline option may change this behavior.

I'm now on this:

sworddragon@ubuntu:~$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-3.19.0-8-generic root=UUID=05338ff8-a226-421b-90a4-1dd45199f783 ro elevator=cfq no_console_suspend


But on executing "echo disk > /sys/power/state" I'm still seeing the issue.

Comment 3 Aaron Lu 2015-03-16 02:59:07 UTC

(In reply to sworddragon2 from comment #2)
> (In reply to Aaron Lu from comment #1)
> > Not a functional problem I suppose?
> 
> After hibernating and booting the system it does boot normally instead of
> loading the state from the hibernation file but currently I'm assuming it
> has something to do with my encrypted swap (dm-crypt) as I don't have
> configured something special which is maybe needed here.

OK.
Distribution seems to have document on how to enable this, maybe you can get some help there.
Google showed me this:
https://help.ubuntu.com/community/EnableHibernateWithEncryptedSwap

> 
> 
> (In reply to Aaron Lu from comment #1)
> > The text "Begin: Loading essential drivers ... done." seems to be what's
> > left in somewhere of the GPU's buffer and on hibernation, it's displayed
> > again.
> 
> I'm always seeing this line at first on booting on the second console that
> appears.

I think this is a distro-specific behavior, instead of a kernel/driver bug. Can you try another distro's live cd to see if this is still the case?

> 
> 
> (In reply to Aaron Lu from comment #1)
> > The no_console_suspend kernel cmdline option may change this behavior.
> 
> I'm now on this:
> 
> sworddragon@ubuntu:~$ cat /proc/cmdline
> BOOT_IMAGE=/boot/vmlinuz-3.19.0-8-generic
> root=UUID=05338ff8-a226-421b-90a4-1dd45199f783 ro elevator=cfq
> no_console_suspend
> 
> 
> But on executing "echo disk > /sys/power/state" I'm still seeing the issue.

Please try another distro, if this doesn't happen, you can file a bug on your distro's bugzilla.

Comment 4 sworddragon2 2015-03-23 21:23:39 UTC

I have tested this with Knoppix 7.2.0 (Linux kernel 3.9.6) and this issue doesn't appear there. I have forwarded this issue now to Ubuntu: https://bugs.launchpad.net/ubuntu/+bug/1435561