I just upgraded my Kubuntu 9.10 "Karmic Koala" from KDE 4.3.4 to 4.4.0 using the backports repository. A note of warning: take a backup.

It took me something like 4 or 5 runs of apt-get dist-upgrade / apt-get -f install to get back a working setup. APT complained about a couple of things (python-qt3-doc conflicting with some newer package which includes the same examples, and Bilbo having been renamed Blogilo) but eventually pulled it through.

I was smart enough to backup the .kde home directory before launching a 4.4 session, and I'm glad I was. First run: Plasma crashed hard on a segfault, and didn't restart. Ok, this happened with some past upgrade already, let's just move away the old .kde home... got back a default desktop. Playing around with widgets, I hit another crash. And another. The culprit was always the Plasma Desktop, actual applications were running fine. Eventually, I moved back the old .kde home except the plasma* files under .kde/share/config/. This gave me back all my old KDE settings, except for Plasma. Win, I thought, and merrily set out to recreate my previous desktop arrangement.

Another crash.

So uhm. I'll try to track down what exactly Plasma doesn't like in my setup (which was, for the record, with two panels on left and right edge; Lancelot and a couple of QuickAccess widgets on the left, task manager and shutdown button on the right; two Plasma "views" and 4 virtual desktops), but if you are planning a similar upgrade, make sure you put aside some time for it, and get a good backup beforehand.

(I guess the question now would be "is it worth it?". Well, KDE does look more polished, applications are faster to launch and more responsive... it does look like we're finally at the point where one could upgrade from a 3.5.x release to 4.x and feel a bit awestruck.)

The upgrade to Kubuntu 9.10 "Karmic Koala" threw me back to the glorious 90s, when installing Linux would invariably require long battles with the infamous XFree config files. Hours and hours wasted trying out magic incantations in order to escape the brutal world of command-line interfaces. !FUN

Anyway, here's a bit background: basically, ATI stopped releasing proprietary Linux drivers for their old cards. So you can either use the old drivers, or move to the open-source ones (a complete rewrite, which only recently got good enough for real use). But here's the problem: the version of (KDE window manager) KWin shipped with Karmic crashes horribly with the old ATI drivers, and recent Xorg releases don't really work well with them anyway. So you haven't much of a choice: move to the free drivers and thank Stallman for inventing the cure to the annoying problem of manufacturers dropping support for products after less than five years.

The problem with the open-source drivers, however, is that running with default parameters will give you shockingly bad perfomance, especially for 2D (weird). I was forced to delve into xorg.conf and turn on all the "turbo-boost" switches I could find. At the moment, I'm getting decent result with the following parameters:

Section "Device"
Identifier      "Configured Video Device"
Driver  "radeon"
Option  "AccelDFS"              "on"
Option  "AccelMethod"           "XAA"
Option  "MigrationHeuristic"    "smart" # "greedy" works well also
Option  "EnablePageFlip"        "on"
Option  "EnableDepthMoves"      "on"
Option  "ColorTiling"           "on"
Option  "FBTexPercent"          "0"
Option  "AGPMode"               "4" # this is the real kicker
Option  "TripleBuffer"          "true"
EndSection

Note AccelMethod being set to XAA. In the future that will probably be EXA (which apparently is a newer algorithm), but my experiments with it included too many crashes for my taste.

There are a few other parameters that I scavenged from Google and man radeon, but they mostly resulted in crashes on my machine (tbh, I'm not sure they were always the guilty party, but better safe than sorry):

• "AGPSize" "128" -- from what I understand, this should just be the amount of video RAM you have.
• "EXAOptimizeMigration" "on" -- relevant only if you use EXA
• "XAANoOffscreenPixmaps" "on" -- no idea what this is, but my card doesn't like it
• "BIOSHotkeys" "on" -- my screen-related Fn-* hotkeys work anyway, even without this parameter
• "AGPFastWrite" "on" -- this hangs X on my laptop (Rock Pegasus Ti)

I put this here so I may remember to search my blog next time instead of wasting time going through random forum threads, but I hope it may be of help to fellow Radeon linuxers. All in all, KDE 4.3 is lovely, but it kinda reminded me that five years is quite a long lifespan for a laptop.

• Upgrade installer choked on finding out that python2.6 was already installed. Had to fall back on hardcore dpkg commands to fix it. I understand most "upgraders" had similar issues. -1
• Keeps complaining that it can't find my uid-identified partitions straight away (slow HAL?). Considering it eventually manages to mount them just fine (and that the uid scheme was forced upon me by a previous Kubuntu), it just seems stupid. Any idea how I could stop the nagging? Meanwhile, -1
• Sluggish. Maybe because KWin would crash on ATI drivers and I had to switch back to the free ones. -5
• Eyecandy is fabulous, and very consistent. Much better than Vista.+1
• Managed to recreate my old desktop setup almost flawlessly. Most 4.0 regressions due to Plasma have finally been addressed. +1
• Many (most?) widgets are useless. Only few of them "get" what Plasma is about. I guess this will be fixed in time. +0
• The Widget Dashboard, once you "get it", is fantastic. Makes things like Quick Launcher absolutely redundant. +1
• Configuration utilities have been somewhat cleaned up, in a long-overdue effort. +1, but for the love of God stop with the Gnome-like zealotry.
• Looks like KNetworkManager won't properly manage my wifi. Somewhat balanced by forcing people (me) to rediscover the joys of full-speed cabled access. Still, -1 (and I'm being generous)
• KPackageKit finally gives us a Qt-based alternative to Synaptic. +1
• the gmail-plasmoid. Never found a decent counterpart for 3.5. +1
• UI to Power Management features is finally as good as anything in the Windows world. Maybe better. +1
• Shortcuts every-flipping-where. One day, I might even use them. +1
• Lots of good repositories for fresh software, without having to jump through hoops. And the ppa/apt-add-repository combo is a winner. +1

Total: +1. So I guess it was all worth.

(posted with this newfangled Bilbo / Blogilo thing. Could this be the day I get a decent blog-writing application?)