Problem: suspend-to-disk + encrypted filesystems

[Hans <hans.ullrich@loop.de>]

Hi folks,

since some months I got problems with suspend-to-disk. 

Running debin/testing I have /usr, /var and /home encrypted. Suspend-to-disk 
worked a long time, whilst the suspend/resume device was /dev/mapper/usr.

But after some update, this does not work any more. Even, when I am using my 
swap partition as suspend/resume device, it does not work.

When resuming, and giving the correct passphrsae to encrypt /usr, the system 
is shutting down and reboots again. Formerly this did not happen, when I gave 
the correct passphrase, I could see the system reading the data from the 
drive, then directly showed the window manager again.

So, I guess, something essentiell has happened to the suspend code. I read, 
that there are problems with encrypted filesystems. And all solutions I found, 
were by using an encrypted swap partition.

Please allow me some questions for the understanding:

1. Did uswsusp and hibernate made changes in its code or philosophy, that 
encrypted filesystems are no more supported?

2. Is it  mandatory necessary, to use swap partition as resume device?

3. As I am using KDE and powerdevil - is it correct that powerdevil is based 
on uswsusp?

4. Tuxonice - is it correct, that tuxonice is only user interface?

5. Entries for the suspend device in uswsusp.conf and /etc/hibernate/
hibernate.conf are different. Which one is the active?

 6. dpkg-reconfigure uswsusp does no more ask for the resume/suspend device. 
And its entry is /dev/someUUID and not /dev/sdaX. I guess, this will be the 
same.

Sorry for my many questions, but I hate it, when things that worked fine before 
and suddenly do not and I do not understand, why this happens. :)

Thank you for any answers.

Best regards

Hans