like i said... i use BOTH.

well, enabling CSSU-devel and doing apt-get upgrade is a recipe for disaster.

You may want to check what exactly packages you have installed from cssu-devel and downgrade them to testing or thumb version

That's why I asked for more details, but I did not see any mention of the OP having done an apt-get upgrade.

It's incredible how many people use that command without realising it's dangers.

well, AFAIK HAM will do the same as apt-get upgrade if -devel repo is enabled, i.e. will pull the highest possible version. So no matter if it is update via HAM or apt-get upgrade, the packages from cssu-devel will still get installed.

...it seems despite certain up-front & seemingly ignored warnings, cssu-devel receives much download love from, err, not really applicable people

Well, until today i had no (fatal) issues i couldn't deal with... i guess there is always a first time

Anyway, finding the exact package is a problem - i tried reverting to my oldest backup (about a month ago) and could still see the problem there which i find to be quite strange, since this entire month i did not have this issue (and i restarted the device several times during). That is why my first instinct was to assume that it is a hardware issue, but then i investigated and found the issue with hildon-desktop process not being loaded, and that is probably the only issue right now - to make it load the way it did before.

well, i am doing my best you know

upstart executes /etc/event.d/hildon-desktop when X starts. But that script merely waits until hildon-desktop is functional (so effectively does nothing).

hildon-desktop itself is run by X (/etc/X11/Xsession.post/20hildon-desktop) using:

dsmetool -c 3 -T 180 -m -17 -t /usr/bin/hildon-desktop

Note that /etc/init.d/hildon-desktop is, AFAIK, not used by Maemo5 at all.

So, probably one or more changes in either

upstart
system-services
hildon-desktop

are the culprit?

EDIT: hildon-desktop 2.2.147.90-1 update didn't change this behavior. I would attached a (partial) syslog, but currently:

MicroB, claws-mail and so on all crash. (It could be HTML-view / control related, though.) At least they worked before that last update.
Opera can't load my DAV-Account website via HTTPS (only that is possible) because of the common & famous encryption-layer related "fatal error (40)", that you can't override.
Helium wouldn't give me a damn file chooser dialogue for HTTP upload ANYWHERE.
Dooble browser wasn't able to start since i installed it.
BT file transfer isn't possible too, because of issues mentioned in <see obexd thread>.
xarchiver couldn't create a .7z archive because it complains about "too many levels of symbolic links", but at least it let me 'zip the d*mn log up.

I 'ate this... it's the pure N900 experience; there are _always_ things which are broken but you rely on because they are, like, basic functionality?. Ok, then scrap that; i have no more time for this today.

Some updates:
i've added as a temporary workaround to a script in "/etc/event.d" (reinob - thanks):

/usr/sbin/dsmetool -c 3 -T 180 -m -17 -f /usr/bin/hildon-desktop

This not only executes hildon-desktop, but also makes sure that if it is being killed, it will be executed again automatically.

i've taken the command from "/etc/X11/Xsession.post/20hildon-desktop" but it seems that this script (the one in /etc/X11/Xsession.post/) is not being executed on system startup for some reason.

my current version of "upstart" package is 0.3.8-68+0cssu3 (i guess this was a recent update). i've noticed that it recommends system-services in its info.
"apt-get upgrade" command currently shows the following:

The following packages have been kept back:
mp-fremantle-community-pr
The following packages will be upgraded:
ke-recv system-services

my current installed version ke-recv is 3.19-15.6
my current installed version system-services is 0.3.8-68+0cssu0
my current installed version mp-fremantle-community-pr is 21.2011.38-1Tmaemo6


i'm currently not upgrading these packages since the device is getting into a boot loop on restart (it loads until the point i can see the desktop and then shuts down). After trying to install these packages i've updated both "/etc/event.d/rcS-late" and "/usr/lib/genfstab.awk" to use ext4 instead of ext3 partition (my optfs is ext4).

another strange issue i've noticed is that the contacts i had on the desktop are missing (and i cannot add these specific contacts from the list of available contacts which means that they are on the desktop, but for some reason cannot be seen). i can see that they exist in:

/var/lib/gconf/apps/osso/hildon-desktop/applets (called osso-abook-applet-100 and osso-abook-applet-72)

any further help will be appreciated.