> I disabled effects with shortcut
> #25 0x00007fcc9f774861 in KWin::Workspace::performCompositing (this=0x10cd010) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/composite.cpp:417

No idea what you believe effects are or how to disable them, but the compositor is still active... (press alt and use the mousewheel on a window - it will change it's opacity)

The crash is in glClear(GL_COLOR_BUFFER_BIT); - that's the famous intel-bug

-> there's sth fundamentally wrong with your setup, do you run several kwin instances on a multiscreen setup or sth. like that?

Hello.
For "effects" i mean desktop effects, that i can disable with shift+alt+f12 shortcut.
I don't use multiscreen,it's only normal laptop with intel card and  i think that is standard setup. What do you see of strange?

The backtrace shows that the effects are not disabled, otherwise you would not encounter this particular crash which is "just" the known intel bug and usually occurs when unredirecting (fullscreen) windows.

So whatever you do, it does not effectively suspend compositing.

-> Run "kcmshell4 keys" select kwin and filter for "suspend", ensure shift+alt+f12 is actually bound to that action.
You can also try "qdbus org.kde.kwin /KWin toggleCompositing"

Hello
I am sure that shift+alt+f12 suspend desktop effects because i can see this on KDE control panel, desktop effects section, and my panel becomes black.
Maybe you can't see that are turned off because when i minimize an application kwin freeze, and the error message come out only when i turn on again (with the same shortcut) the desktop effects.
This happen only with maximized windows.

Please
- open a terminal (konsole)
- suspend compositing
- run "qdbus org.kde.kwin /KWin compositingActive" (w/o quotes)
- ensure the reply is "false"
- trigger the crash
- check and post the backtrace

The crash is in the compositor but the compositor (effectshandler & scene) should be deleted after you suspend compositing - that's why a system with suspended compositing is no way able to trigger this crash.

Conclusion: compositing cannot be suspended.

If you successfully suspended compositing and still get this crash the only alternative is that sth. reactivates it. Do you have a rule on the to be minimized to block compositing?

Hello, and thank you for you patience.
That's what i have done:
-Konsole: qdbus org.kde.kwin /KWin compositingActive --> False
-I crashed kwin minimizing rekonq --> Freeze
-Re-enableb desktop effects --> Kwin error assistant appear with this backtrace:
I have no rules on minimizing this sholud be pretty standard config.

Application: KWin (kwin), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f9cc66b7780 (LWP 1625))]

Thread 3 (Thread 0x7f9cab645700 (LWP 1652)):
#0  0x00007f9cc5ef3263 in select () from /lib/libc.so.6
#1  0x00007f9cc16acc34 in ?? () from /usr/lib/libQtCore.so.4
#2  0x00007f9cc15d447b in ?? () from /usr/lib/libQtCore.so.4
#3  0x00007f9cc1343ede in start_thread () from /lib/libpthread.so.0
#4  0x00007f9cc5ef960d in clone () from /lib/libc.so.6

Thread 2 (Thread 0x7f9ca3fff700 (LWP 1655)):
#0  0x00007f9cc1347aa4 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f9cc29a9717 in ?? () from /usr/lib/libQtScript.so.4
#2  0x00007f9cc29a9749 in ?? () from /usr/lib/libQtScript.so.4
#3  0x00007f9cc1343ede in start_thread () from /lib/libpthread.so.0
#4  0x00007f9cc5ef960d in clone () from /lib/libc.so.6

Thread 1 (Thread 0x7f9cc66b7780 (LWP 1625)):
[KCrash Handler]
#6  0x00007f9caabd4e53 in ?? () from /usr/lib/xorg/modules/dri/i965_dri.so
#7  0x00007f9caabd4970 in ?? () from /usr/lib/xorg/modules/dri/i965_dri.so
#8  0x00007f9caabbef70 in brw_upload_state () from /usr/lib/xorg/modules/dri/i965_dri.so
#9  0x00007f9caabacaa7 in brw_draw_prims () from /usr/lib/xorg/modules/dri/i965_dri.so
#10 0x00007f9caa81e193 in ?? () from /usr/lib/libdricore.so
#11 0x00007f9cc23d5a87 in KWin::GLVertexBufferPrivate::corePainting (this=0x2701d50, region=<optimized out>, primitiveMode=4) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwinglutils.cpp:1188
#12 0x00007f9cc23d5b85 in KWin::GLVertexBuffer::render (this=0x2c35d80, region=<optimized out>, primitiveMode=4) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwinglutils.cpp:1297
#13 0x00007f9cc626cf90 in renderQuads (normalized=<optimized out>, tex=<optimized out>, quads=<optimized out>, region=..., this=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene_opengl.cpp:788
#14 KWin::SceneOpenGL::Window::renderQuads (this=<optimized out>, region=..., quads=<optimized out>, tex=<optimized out>, normalized=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene_opengl.cpp:768
#15 0x00007f9cc62738c8 in KWin::SceneOpenGL::Window::performPaint (this=0x2a81b90, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene_opengl.cpp:592
#16 0x00007f9cc625ea2e in KWin::Scene::finalDrawWindow (this=<optimized out>, w=<optimized out>, mask=1, region=<optimized out>, data=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:438
#17 0x00007f9cc627e185 in KWin::EffectsHandlerImpl::drawWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:286
#18 0x00007f9ca8685bed in KWin::BlurEffect::drawWindow (this=<optimized out>, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects/blur/blur.cpp:389
#19 0x00007f9cc627e11b in KWin::EffectsHandlerImpl::drawWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:283
#20 0x00007f9cc405ecca in KWin::Effect::drawWindow (this=<optimized out>, w=0x2bf8fc0, mask=1, region=<optimized out>, data=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwineffects.cpp:181
#21 0x00007f9cc627e11b in KWin::EffectsHandlerImpl::drawWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:283
#22 0x00007f9cc625daa6 in KWin::Scene::finalPaintWindow (this=<optimized out>, w=0x2bf8fb0, mask=1, region=<optimized out>, data=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:429
#23 0x00007f9cc627e485 in KWin::EffectsHandlerImpl::paintWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:249
#24 0x00007f9cc405edca in KWin::Effect::paintWindow (this=<optimized out>, w=0x2bf8fc0, mask=1, region=<optimized out>, data=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwineffects.cpp:156
#25 0x00007f9cc627e41b in KWin::EffectsHandlerImpl::paintWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:246
#26 0x00007f9ca8671308 in KWin::TranslucencyEffect::paintWindow (this=<optimized out>, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects/translucency/translucency.cpp:108
#27 0x00007f9cc627e41b in KWin::EffectsHandlerImpl::paintWindow (this=0x2bac350, w=0x2bf8fc0, mask=1, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:246
#28 0x00007f9cc625e48b in KWin::Scene::paintWindow (this=<optimized out>, w=0x2a81b90, mask=1, region=<optimized out>, quads=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:385
#29 0x00007f9cc625f329 in KWin::Scene::paintSimpleScreen (this=0x2808ac0, orig_mask=0, region=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:330
#30 0x00007f9cc625d9d4 in KWin::Scene::finalPaintScreen (this=0x2808ac0, mask=0, region=<optimized out>, data=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:198
#31 0x00007f9cc627e003 in KWin::EffectsHandlerImpl::paintScreen (this=0x2bac350, mask=0, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:222
#32 0x00007f9cc405ee37 in KWin::Effect::paintScreen (this=<optimized out>, mask=0, region=<optimized out>, data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwineffects.cpp:141
#33 0x00007f9cc627dfab in KWin::EffectsHandlerImpl::paintScreen (this=0x2bac350, mask=0, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:219
#34 0x00007f9cc405ee37 in KWin::Effect::paintScreen (this=<optimized out>, mask=0, region=<optimized out>, data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/libkwineffects/kwineffects.cpp:141
#35 0x00007f9cc627dfab in KWin::EffectsHandlerImpl::paintScreen (this=0x2bac350, mask=0, region=..., data=...) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/effects.cpp:219
#36 0x00007f9cc62605c8 in KWin::Scene::paintScreen (this=0x2808ac0, mask=0x7fff84da68fc, region=0x7fff84da69c0) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene.cpp:156
#37 0x00007f9cc62743ed in KWin::SceneOpenGL::paint (this=0x2808ac0, damage=..., toplevels=<optimized out>) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/scene_opengl_glx.cpp:459
#38 0x00007f9cc625a861 in KWin::Workspace::performCompositing (this=0x270bf40) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/composite.cpp:417
#39 0x00007f9cc16e34dc in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#40 0x00007f9cc088ab4c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#41 0x00007f9cc088efca in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#42 0x00007f9cc59f1e06 in KApplication::notify (this=0x7fff84da76d0, receiver=0x270bf40, event=0x7fff84da70a0) at /chakra/desktop-testing/kdelibs/src/kdelibs-4.8.3/kdeui/kernel/kapplication.cpp:311
#43 0x00007f9cc16cedce in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#44 0x00007f9cc16ff672 in ?? () from /usr/lib/libQtCore.so.4
#45 0x00007f9cc16ff828 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#46 0x00007f9cc092b3b7 in ?? () from /usr/lib/libQtGui.so.4
#47 0x00007f9cc16cdb1f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#48 0x00007f9cc16cdda8 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#49 0x00007f9cc16d2a48 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#50 0x00007f9cc621515e in kdemain (argc=1, argv=0x7fff84da7858) at /chakra/desktop-testing/kde-workspace/src/kde-workspace-4.8.3/kwin/main.cpp:541
#51 0x00007f9cc5e36455 in __libc_start_main () from /lib/libc.so.6
#52 0x0000000000400651 in _start ()

WOW, i have something new.
This strange crash happens only when  PANEL AUTOHIDE ON, minimizing a maximized window.

(In reply to comment #6)
> -I crashed kwin minimizing rekonq --> Freeze
Ok, this is the severe part.
Please elaborate on "crash" and "freeze"
Does kwin segfault and do you get a backtrace for this?
If not,  what freezes and how does that manifest?

> -Re-enableb desktop effects --> Kwin error assistant appear with this
Aha ;-)
It's likely some follow up - the intel driver gets confused about the current context and then crashes. That's "normal" (unfortunately, but the bug in the driver is afaik rather tricky)

When i minimize the window the screen seems locked, nothing respond except the mouse pointer (freeze?). I can switch on TTY1 to reboot.
I notice that if i have more application opened, this happen when i minimize last window, when desktop should appear. Panel autohide must be enabled.

do alt+tab or alt+f2 (krunner) still work?
do plasmoids on the desktop still update?
do you have other (non auto-hiding) panels?

No, I have only one (and autohide)  panel.
When kwin "crash" i can see only the maximized (freezed) window. As soon as i type Alt+F2 nothing appears, but mouse cursor changes in the area where shoud be krunner, that appear when i re-enable effects, together with KDE bug assistant.

[assume a long list of cotradicting conclusions i deleted to not confuse anybody - this is really weird]

does the content of the autohiding panel matter, ie. does it also happen with a blank one?
(if not: try removing just the taskbar next)

Same issue with only an empty autohide panel.