A suggestion has been made on the Mandriva Bugzilla (http://qa.mandriva.com/show_bug.cgi?id=36192) that KDE4 is now checking the machine's capabilities to determine whether to activate or deactivate 3D features and may have incorrectly decided my video card supports those features.

1. Is this plausible? The problem appeared with Mandriva's latest KDE4 updates, which I believe are RC2.

2. If it is plausible, is there any way to force deactivation of 3D features (command line or config files)?

Compositing now does not activate automatically. Can you attach your ~/.xsession-errors for the problem?

Created attachment 22834 [details]
.xsession-errors file when starting kde4, compressed with bzip2

As requested in Comment #2

I had this, too, on both my two computer, one of them is running desktop effects and one is not (AIGLX etc. deactivated).

I have this problem too. I have an NVIDIA Geforce 7800GT, which can handle the 3D effects easily.

I have encountered this problem too, with openSUSE 10.2 and "RC2++" packages (KDE version 3.97.2). My graphics card is a NVidia Geforce 7800 Go with the nvidia driver.

When starting KWin inside a KDE 3 session (using the --replace command) a black screen appears so that I can only see the mouse. I can, however, open my Yakuake and type /opt/kde3/bin/kwin --replace which solves the problem. It is like KWin produces a root window placed in the foreground.

P.S.: Everything worked fine with an earlier 3.97 version (could be 3.97.1 or an earlier 3.97.2) until I updated yesterday (my first update since 22-12-2007 as I had only a dialup connection).

Created attachment 22877 [details]
my .xsession-errors (bzip2 compressed)

This is my .xsession-errors after logging into a KDE 4 session from KDM 3. The
desktop is functional but everything but the splash screen is invisible.

For me, the problem is solved by changing the render type from OpenGL to XRender.

I also get this problem, but only sometimes.

I think it can be tracked down to the blur or transparency options.  If I enable these then they work until I log back in.  I can always fix it by removing .kde.

I am using nvidia 169.07 drivers which should be free of the black window bug.

> I can always fix it by removing .kde. 
Removing .kde/share/config/kwinrc is more than sufficient. ;)

Ok, i did a litle bit of testing, the setting, that does definitely trigger this is:
kwin4_effect_blurEnabled=true

The other settings, as far as I tested them, don't seem to have anything to do with it. It even happens, if all other settings are set to false (except Composite of course), although Blur without transparency doesn't really make sense.

Nvidia drivers are 100.14.23 (the latest ones, afaik).

Video card is (shouldn't be relevant I guess):
07:00.0 VGA compatible controller: nVidia Corporation G80 [GeForce 8800 GTS] (rev a2)

Actually I just found out, that it does also not work, when there are no effects set at all.
I did now track it down to this:

kwin4_effect_blurEnabled=false
kwin4_effect_fadeEnabled=true
--> ok

kwin4_effect_blurEnabled=false
kwin4_effect_fadeEnabled=false
--> bug (I'm not entirely sure about this one, but 90%)

kwin4_effect_blurEnabled=true
--> bug (other settings don't change anything here)

Hope others can reproduce it.

> For me, the problem is solved by changing the render type from OpenGL to XRender. 

Well, the reason is quite simple: With XRender Blur is not supported, KWin tells you that.
There is another reason. When starting KDE4 with XRender it will deactivate all effects on startup. You have to go to the effects menu and press apply, then they are activated.
But it can be tested with kwin --replace and it shows, that with XRender the problem with fade seems to be gone.

Back to OpenGL. The behaviour is also reproducable with kwin --replace. At least on my computer. ;)

Created attachment 22915 [details]
kwin output

It seems to be not that much, is there a higher debug level, that can be
activated?

Re: Comments #10-#15
None of that works for me.

Re: Comment #9
Pardon the dumb question, how do you change the render type to XRender?
(I did check X and related man pages, nvidia README, googled, etc. before asking.)

AAW: In System Settings, at "Workspace > Workspace effects" (or how it is called in English), open the advanced options and change the compositing type.

AAW: You get this with the default config for kde4?
Then we are really talking about different issues here.

Re: Comment #17
Unfortunately I can't access the KDE4 menu from the keyboard. Does anyone happen to know what to enter in which config file?

Re: Comment #18
That is correct. Ever since the last KDE4 release (RC2, I guess), it happens even with a brand new user. I had no problem prior to the update.

Hm, then it is a different problem.
I've compiled a lot of sources after RC2 and got this only since a few days (though I didn't do a recompile from 19.12. to approx 29.12).

But with a fresh config I don't have this.

What happens if you disable Composite and AIGLX in xorg.conf?

Section "Extensions"
        Option          "Composite" "false"
EndSection

Section "ServerFlags"
        Option          "AIGLX" "off"
EndSection

Re: Comment #20
With Composite off, the black screen is replaced by the KDM background. Everything else is the same as my initial report.

With Composite and AIGLX off, I also lose all window decorations (title bar, ability to resize, etc.)

That means, that kwin crashed.

Does it work, if you then open a konsole (Alt+F2) and run kwin manually?

*** Bug 155380 has been marked as a duplicate of this bug. ***

Re: Comment #22
Yes, "kwin --replace" works. Not only that, kwin no longer crashes on subsequent logins. The original problem remains however.

Did you try to run kde4 via startkde directly instead of kdm?
Did you try with a kwinrc file, that is known to be sane?

BTW: There is another bug report (bug 155417) with the same issue (I guess), he has got a Intel card, too, but I think he has the problem, that we Nvidia users face when we enable blur and not yours.

Created attachment 22949 [details]
kwinrc with disabled compositing

Could you try with this kwinrc?
It has explicitly disabled compositing and it should work.

Re: Comment #25
Starting kde4 from init 3 command line gives same result as starting from KDM.

I haven't made any changes to Mandriva's default kwinrc, which is:
   [Style]
   BorderSize=1
   ButtonsOnLeft=MS
   ButtonsOnRight=HIAX
   CustomButtonPositions=false
   PluginLib=kwin3_oxy
   ShowToolTips=true

Re: Comment #26
Tried with kwinrc from attachment 22949 [details]. No change.

General Comment:
I'm now in the process of upgrading to Mandriva's packaging of KDE 4.0.0. Packages are still showing up on the mirrors, resulting in some (hopefully) temporary phonon library mismatches, but so far the original problem remains.

After this morning's updates (Mandriva cooker, the development branch), I have a visible desktop. The only KDE4 packages I installed were extragear-plasma-4.0.0-1mdv2008.1 and libplasma1-4.0.0-1mdv2008.1
which replaced kdeplayground4-plasma-3.97.1-0.752113.2mdv2008.1 and libplasma1-3.97.1-1mdv2008.1 respectively. 

I'm going to hold off closing this for a few days, just to be certain the problem is solved.

I think this bug is because of KWin and not of Plasma, so un/installing plasma packages shouldn't help. Didn't you turn off an effect (blur?)?

Lukas

Re: Comment #29
I turned off blur, composite, AIGLX, and followed every other suggestion anyone has made on this bug report. All of them were greatly appreciated, but they didn't cure the problem. After my daily update this morning, that problem went away. The two packages I mentioned in Comment #28 were the only KDE4 packages installed. I'm not advancing any theories, just reporting what happened.

I had this problem too but, following the suggestion about turning off the blur effect, the problem (in my case) was solved. 
Don't know if can help, but I got an Nvidia video card (8600M GS, driver version: 169.07).

I have the same problem, but with an ATI graphics card (Radeon 9200SE, using the "radeon" driver). It appears every time with OpenGL as renderer -- no matter which effect is selected.

- If somebody has a problem caused by the blur effect, please file a separate bugreport for that - blur is definitely not enabled by default, so this is not that problem.
- Please see http://techbase.kde.org/Projects/KWin/4.0-release-notes for KWin's 4.0 release notes that include information on setting up and troubleshooting - if something there helps to prevent this problem, please say what is was. If not, I'll need 'glxinfo' output.

I opened bug 156018 for the blur effect issue.

Yesterday I disabled the fade effect (blur is always disabled), then compiled the latest branch (svn rev r762910). This morning every time I tryed to login, I got a black screen, with only the mouse. Just pressing ctrl-f8 (enabling the Desktop Grid), made the complete desktop appear and completely usable.
I'm on a NVIDIA 7600GS 256mb driver 169.07. It used to work flawlessy before with fade enabled, but was slow.
This is my actual kwinrc:

[$Version]
update_info=kwin3_plugin.upd:kde3.2,kwin_on_off.upd:kwin_on_off,kwin_focus2.upd:kwin_focus2,kwin.upd:kde3.0r1,kwin.upd:kde3.2Xinerama,kwin_focus1.upd:kwin_focus1

[Compositing]
Backend=OpenGL
Enabled=true
GLDirect=false
GLMode=TFP
GLTextureFilter=2
GLVSync=false
HiddenPreviews=0
XRenderSmoothScale=false

[Desktops]
Name_1=
Name_2=
Name_3=
Name_4=
Number=4

[Plugins]
kwin4_effect_blurEnabled=false
kwin4_effect_boxswitchEnabled=true
kwin4_effect_desktopgridEnabled=true
kwin4_effect_dialogparentEnabled=true
kwin4_effect_diminactiveEnabled=false
kwin4_effect_explosionEnabled=false
kwin4_effect_fadeEnabled=false
kwin4_effect_fallapartEnabled=false
kwin4_effect_invertEnabled=false
kwin4_effect_loginEnabled=true
kwin4_effect_logoutEnabled=true
kwin4_effect_lookingglassEnabled=false
kwin4_effect_magnifierEnabled=false
kwin4_effect_maketransparentEnabled=false
kwin4_effect_minimizeanimationEnabled=false
kwin4_effect_mousemarkEnabled=false
kwin4_effect_presentwindowsEnabled=true
kwin4_effect_scaleinEnabled=false
kwin4_effect_shadowEnabled=true
kwin4_effect_sharpenEnabled=false
kwin4_effect_showfpsEnabled=false
kwin4_effect_showpaintEnabled=false
kwin4_effect_taskbarthumbnailEnabled=true
kwin4_effect_thumbnailasideEnabled=false
kwin4_effect_trackmouseEnabled=true
kwin4_effect_zoomEnabled=true

[Style]
BorderSize=0
ButtonsOnLeft=MS
ButtonsOnRight=HIA__X
CustomButtonPositions=false
PluginLib=kwin3_oxygen
ShowToolTips=true

*** This bug has been confirmed by popular vote. ***

Created attachment 23634 [details]
.xsession-error in case of black login screen

First, some informations perhaps worth mentioning, xorg & nvidia-driver version :

$ dpkg -l xserver-xorg nvidia-kernel-2.6.24-1-686
ii  nvidia-kernel-2.6.24-1-686                  169.09-1+2.6.24-4
ii  xserver-xorg                                1:7.3+10


1. this appens whatever the konsole size is (usually resizing from ~1600x1000 -> ~1000x600, but same appens when I do ~200x200 -> ~300x300)

2.
 - if I fully disable desktop effects Enabled=false in the [Compositing] section, there is not more slowdown (but no more transparency too)
 - if I disable all effects, I get a black screen on login, as reported by someone else in bug #154637 (see attached xsession-error, even if I don't think there's much interesting here, I'll also post it on #154637)
 - if I just enable the fade effect, then the behaviour is the same as with all effects enabled.

opps, I'm really sorry, I posted the above message on the wrong bug ...
The attached .xsession-error is relevant tough

I just spend one night investigating this bug...
I think people are referring to different problems inside this bug report.

The problem I'm addressing below is "black screen with ati 8.0{1,2} drivers and composite enabled".

The problem is (in my case) somehow triggered by the deactivation of the kwin4_effect_fadeEnabled (setting it to flase). This is always reproducible.

On the other hand sometimes the problem occurs even without disabling the Fade Effect. In this case the only fix is to respawn a new Xorg.

I tried all sort of kwin config options (even brute force using "divide et impera") to track thi problem. I hope my guesses are useful to someone else.

Created attachment 23692 [details]
My Xorg.conf

This is the Xorg.conf that is working for me using for fglrx 8.0{1,2}.

Created attachment 23694 [details]
My kwinrc

This how my kwinrc is set to make things work.

Created attachment 23696 [details]
The output of kwin when black screen is shown

.xession-errors is clean:
$ rm .xsession-errors
$ kwin
#kill kwin
$ ls .xession-errors
ls: .xsession-errors No such fileor directory

Created attachment 23697 [details]
My glxinfo output

Finally here it is what glxinfo outputs :-)

I have the same problem on yesterday's KDE-SVN. I have blur and composite desiabled. I use nvidia card with the newest drivers installed.

I had the same problem today - kwin started up as a black screen. My compositing section in kwinrc looked like this:
[Compositing]
Enabled=true

Merely changing 'true' to 'false' restored kwin as normal. Using the XRender backend works okay, though with some unrelated bugs. No black screen, though.

My card is an ATI radeon that doesn't support AIGLX - no direct rendering, no 3D acceleration at all.

I had the same problem, but just solved it. I followed the directions of a Gentoo howto on how to enable AIGLX (http://gentoo-wiki.com/HOWTO_AIGLX). I am using the fglrx driver version 8.47.3-3 with x.org 7.3+10 on Debian unstable.

An upgrade to hardy fixed the problem for me.

Can somebody still reproduce this problem after r807454 (r807453 in 4.0 branch)?

The effects work, no black desktop, but Both browser and Mailclient (FF and TB) are invisible when desktop effects are active.
Besturingssysteem:  Linux 2.6.25.3-2-default x86_64
  Current user:  oddball@AMD64x2-sfn1
  System:  openSUSE 11.0 (x86_64) Beta3
  KDE:  4.0.4 (KDE 4.0.4 >= 20080505) "release 8.1"

Please don't hijack bugreports (-> bug #160393).

Sorry, not my intention.;)
I was never able to get this far..!
Trying to reproduce, as you asked, made this side-effect visible...
(i was told by You not to use the effects until the bugs were fixed, remember?)
Thnx for pointing me to the other one, it matches my bug.

Closing as fixed unless somebody can still confirm the problem.

I can confirm that this bug is still happening, at least to me.  I'm running KDE 4.0.4 on Fedora Core 9 (with fedora 8's Xorg server installed) with an nvidia Quadro video card.  When I have blur enabled, the screen starts up black, but pressing control-F8 will show me my desktop and it will work after that (note that fade and blur effects work just fine after that).  

*** Bug 163313 has been marked as a duplicate of this bug. ***

*** Bug 163734 has been marked as a duplicate of this bug. ***