Ubuntu

Screen flickers or blanks every 10 s with KDE4

Reported by crwl on 2008-10-05
194
This bug affects 15 people
Affects Status Importance Assigned to Milestone
kdelibs
Confirmed
Medium
kdebase-workspace (Ubuntu)
Undecided
Unassigned
xserver-xorg-video-radeonhd (Ubuntu)
Undecided
Unassigned

Bug Description

Binary package hint: kwin

After yesterday's upgrade in Intrepid, the whole KDE desktop is flickering - vertical lines very briefly show up on the screen about every 10 seconds, which makes desktop usage really distracting. The flickering effect is hard to describe, but it occurs on the whole screen and only when running KDE 4. I'm using the open source radeonhd driver with Radeon HD 3850. I tagged the bug to be in kwin, but it might as well be in libplasma2 or kdebase or in any other package that provides KDE 4 basic technologies.

crwl (crwl) wrote :

Switching kwin to metacity within KDE session doesn't seem to help, so the culprit probably isn't kwin but something else. GNOME works fine.

Jonathan Thomas (echidnaman) wrote :

Probably either the driver or Xorg.

Auke Latour (auke-public) wrote :

I can confirm this.

I have the same behaviour on my notebook (Acer Aspire 3610)

00:00.0 Host bridge: Intel Corporation Mobile 915GM/PM/GMS/910GML Express Processor to DRAM Controller (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)

Changed in xserver-xorg-video-radeonhd:
status: New → Confirmed
Auke Latour (auke-public) wrote :

Additional info:
The KDE4 login screen is not flickering. Once logged in, the periodical flickering behaviour (8sec) starts.

crwl (crwl) wrote :

Same here, login screen doesn't flicker, neither does Gnome session.

05:00.0 VGA compatible controller: ATI Technologies Inc Radeon HD 3850

Different display adapters and drivers - probably a Xorg or KDE4 bug. I'm betting KDE4 - Xorg doesn't seem to have been updated for a while and this just began occurring yesterday. I've been using Intrepid for several weeks now, running aptitude dist-upgrade daily.

Same here, using Intrepid for weeks and updating daily. Didn't update during the weekend and today's (monday's) update triggered the annoying flickering behavior. These are the packages that were updated today:

update-motd; landscape-common; landscape-client; libgomp1; gcc-4.3-base; libstdc++6; cpp-4.3; gcc-4.3; g++-4.3; libstdc++6-4.3-dev; libgcc1; binutils; python2.5; python2.5-minimal; libqt4-opengl-dev; libqt4-dev; libqt4-xmlpatterns; qt4-qtconfig; libqt4-qt3support; libqt4-gui; libqt4-designer; libqt4-core; libqt4-script; libqt4-dbus; libqt4-test; libqt4-webkit; libqt4-assistant; libqt4-help; libqt4-network; libqt4-sql-mysql; libqt4-sql; libqt4-svg; libqt4-opengl; libqtgui4; libqt4-xml; libqtcore4; kdelibs5-dev; kdelibs-bin; kdelibs5-data; kdelibs5; adept; binutils-static; libck-connector0; consolekit; gwenview; kamera; libkdecorations4; libkwineffects1; kde-window-manager; kdebase-workspace-bin; libplasma2; kdebase-workspace-data; kdebase-workspace-libs4+5; kdm; kgamma; kgrubeditor; klipper; kruler; ksnapshot; ksysguardd; ksysguard; libavutil49; libavcodec51; libpam-ck-connector; libpostproc51; linux-libc-dev; linux-restricted-modules-common; linux-source-2.6.27; splix; systemsettings; xserver-xorg-input-evdev; xserver-xorg-video-radeon; xserver-xorg-video-ati; kcolorchooser; kdegraphics-strigi-plugins; kolourpaint4; konqueror-plugin-searchbar; libksane0; libokularcore1; mencoder; mplayer; okular; skype; skype-common; linux-image-2.6.27-5-generic; linux-restricted-modules-2.6.27-5-generic; alsa-oss; linux-generic; linux-image-generic; linux-restricted-modules-generic; linux-headers-2.6.27-5; linux-headers-2.6.27-5-generic; linux-headers-generic; libkipi5; libkipi-common

I don't think it's the new kernel's fault because I booted with the old kernel and the problem continues. This is my video card (from lspci):

00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)

Oh, I forgot to mention: changing the resolution doesn't do any good. I can't change refresh rate so I didn't try that. Also, disabling desktop effects doesn't solve the problem.
Thanks.

ibi (wjbleck) wrote :

I've got a similar issue running the Intel 910GM series as well. My flicker seems to be redrawing elements of the desktop in different locations, not just vertical lines.
good luck guys

My flickering also works like ibi's. Not vertical lines, but redrawings of parts of the screen.

An interesting fact: I recorded a video of the desktop using krecordmydesktop (frontend for recordmydesktop) and then I watched it in another computer (running Windows) and there is no flickering at the capture. recordmydesktop seems to receive the screen data before the monitor does, and somewhere between recordmydesktop and the monitor there's something wrong...

Hope that helps (in case any of the developers knows how recordmydesktop words, it could).

Tormod Volden (tormodvolden) wrote :

Do you get flickering when running the "xrandr -q" command? Is it the same?

Aurélien COUDERC (coucouf) wrote :

I can also confirm the bug on my machine : flickering horizontal lines every few seconds.
01:00.0 VGA compatible controller: ATI Technologies Inc RV670PRO [Radeon HD 3850]

It is *indeed* the same type of output I get when running "xrandr -q" !!

sciasbat (fabio-forno) wrote :

I confirm the problem with this card
00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)

And I also confirm that the same flickering is reproduced by running xrandr -q

crwl (crwl) wrote :

Yes, xrandr -q reproduces the same flickering on my Ati system with radeonhd driver.

I can also confirm xrandr -q reproduces the same flickering here.

00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)

Tormod Volden (tormodvolden) wrote :

This is the KDE equivalent to bug #245383. A component of KDE is calling XRRGetScreenResources excessively. And for many cards/drivers/setups this causes a screen flicker. Although some drivers, like -ati, have been improved to avoid flickering in many cases, the best would be to fix KDE in the same way as gtk+2.0 was fixed.

Mark J. Schmidt (mrkjschmidt) wrote :

Also have Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller and have the same issue. And sometimes if I restart x it randr will crash. Flickering still happens but it does crash.

Is it possible to revert a (some) package(s) to a previous version until the issue is fixed? Does anyone know which packages and where to get the previous versions?

Any other workarounds available?

Thanks

Aurélien COUDERC (coucouf) wrote :

This was fixed for me with one of the last two days updates. A few dozen of packages were updated so I don't know exactly which one did it.

Mark Hammond (thewhymy) wrote :

However, this was not fixed for me (00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03))

For me neither. I have the same card as Mark and I'm still experiencing the flickering.

00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)

crwl (crwl) wrote :

KDE4 still flickers with the radeonhd driver too.

ibi (wjbleck) wrote :

I no longer get flickering with the
00:02.1 Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)
card, excepting once each logon, but I can still force it with xrandr -q. It was fixed for me with the update on October 8th.

Mark J. Schmidt (mrkjschmidt) wrote :

Exact same results after upgrade as ibi, same card same results exactly.

Aurélien COUDERC (coucouf) wrote :

I reported the issue was solved a bit too fast.
It didn't happen anymore yesterday for some reason but it is definitely there again today (with radeonhd)...

ibi (wjbleck) wrote :

I can confirm that after another restart mine has started flickering again too. I spoke too soon.

ilowman (ianl-eidosnet) wrote :

Mine disappeared for a while but has returned after a restart. I have a Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03) in my Acer Laptop.

MoonRise (moonrise7) wrote :

I posted this on this Bug Reports as my original bug report was tagged as duplicate and move to this one, but this bug report here sounds like my issue. The Link --> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/275152

My original post:
I can verify this with my ACER 3618 laptop with 2GB RAM and the Intel GMA915. I have tested on other machines that have the GMA3100 display card and it does not occur with those, at least not that can be seen by the eye. Running Kubuntu Intrepid 8.10 up to date as of 2008-10-09 8:00am EDT. The flickering occurs between 7 and 12 seconds, does it very periodic. Why it does not affect the GMA3100 when it is using the same driver, I'm not sure, but it could have to do how it is connecting to the GMA915 vs GMA3100. I've read of a lot of this problem on the Ubuntu and Kubuntu sites. I've tried Ubuntu and it does not do this, ONLY Kubuntu.

MoonRise (moonrise7) wrote :

Well...I was able to get the Ubuntu Live-CD to flicker the same way as Kubuntu. It doesn't do it at the 7 to 12 second frequency though. Only when you do a certain function and that is:

Control Center --> Hardware --> Screen Resolution.

As soon as I click Screen Resolution, it flickers just like mine is doing under Kubuntu. The only difference is that is stops once the Screen Resolution window appears.

ilowman (ianl-eidosnet) wrote :

I've managed to get the flickering to stop by killing the kded4 process, unfortunately I have no idea what kded4 is for but keyboard shortcuts seem to have stopped working! :)

ilowman (ianl-eidosnet) wrote :

I've found out what kded4 is now and the problem is the Detecting RANDR (Monitor) changes service.
If you stop that service in system settings the flickering stops and kded4 can still be run.

MoonRise (moonrise7) wrote :

I can verify what iloman wrote. Disabling that service has stopped the flickering.

MoonRise (moonrise7) wrote :

I can verify what ilowman wrote. Disabling that service has stopped the flickering.

I can also confirm that stopping either kded4 or the Detecting RANDR (Monitor) changes service stops the flickering. Can anyone say what stops working when this service is disabled? I'm guessing KDE won't be able to detect new monitors and maybe I wouldn't be able to use an external CRT/beamer?

savasten (savasten) wrote :

Also confirming ilowman's observation killing kded4 does fix the screen flicker for me. Then I noticed my hotkeys not working so I restarted kded4 using krunner the screen flicker was still gone.

dipsol (martin-diphoorn) wrote :

I can verify what iloman wrote. Disabling that service has stopped the flickering.

For people who cannot find this option:
1. go to System settings in the menu
2. Press the Advanced tab
3. Select the Service Manager
4. Stop the Detecting RANDR(monitor) changes
5. Also tick the checkbox use, so it won't startup again
6. Press apply and close the window

I hope you're flickering is gone now!

Richard Johnson (nixternal) wrote :

AHHH! You guys rock! This totally does help. What I will do is put up a blog post that shows up on Planet Ubuntu and Planet KDE just in case anyone else is experiencing this problem. Great job on figuring this one out as it has been killing me for the past few days.

Yves Marcoz (yves-marcoz) wrote :

I was experiencing the same flickering with my dual-monitor setup in KDE4. I disabled the TV and TMDS-1 output (I got the names from xrandr, which was showing them as additional outputs to LVDS and VGA), by changing my /etc/X11/xorg.conf file with the following options:

Section "Device"
        Identifier "Configured Video Device"
        Driver "intel"
        Option "monitor-TMDS-1" "dvi"
        Option "monitor-TV" "tv"
        Option "monitor-VGA" "vga"
        Option "monitor-LVDS" "lvds"
EndSection

Section "Monitor"
        Identifier "dvi"
        Option "Ignore" "true"
EndSection

Section "Monitor"
        Identifier "tv"
        Option "Ignore" "true"
EndSection

Paul Fee (pfee) wrote :

Does this issue affect kubuntu 8.04 with KDE4.1.2 (installed via http://ppa.launchpad.net/kubuntu-members-kde4/ubuntu)?

I've been getting flickers (as if the DVI signal had been removed and then added again). However unlike the other posts here, "xrandr -q" does not reproduce the flicker.

Also the "Detecting RANDR(monitor) changes" service isn't listed when I followed the System settings advice mentioned previously. Any workaround advice for 8.04 users? Would upgrading to 8.10 be the best solution?

I have a Thinkpad T42p with ATI FireGL Mobility T2 graphics. I'm using an external display connected to DVI-0, internal (LVDS) is disabled via "xrandr --output LVDS --off".

krangal (eduard-mengel) wrote :

Kubuntu 8.04 with KDE 4.1.2 workd for me without flicker.

For me (now in Intrepid) the screen flickered but Ilowman was right.
His tip helped with the flicker problem but did not solve the real problem.

Terry (terry-kryogenic) wrote :

I did not get flickering but I noticed spikes in Xorg every ~10 seconds. These spikes were visibly noticeable to me during video playback. xrandr -q does not reproduce the problem in my case, it seems to be more of a prolonged thing compared with the spikes. Disabling "Detecting RANDR(monitor) changes" did however stop the problem.

Changed in kdelibs:
status: Unknown → New

OK, let's summarize this:

- KDE4's "detect RandR (monitor) changes" service (part of kded4) calls upon XRRGetScreenResources() every 10 seconds (see Tormod's comment above, https://bugs.launchpad.net/ubuntu/+source/meta-kde/+bug/278471/comments/15). XRRGetScreenResources() is reportedly slow.

- R&R can then wreak havoc on the display, in that some drivers apparently (I cannot quote the source) disconnect an ENABLED output in order to check if another previously disconnected output has been hotplugged.

Say, on my i945GM-based laptop, I have DVI-D output (TMDS-1, external display) and LVDS (internal) enabled, and XRandR disables TMDS-1 to check for TV (no connectors available, neither on laptop nor docking station) or VGA presence.

- For some people including myself, disabling the TV output is a viable workaround.
See Bug #147073, specifically
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/147073/comments/4
See http://www.thinkwiki.org/wiki/Xorg_RandR_1.2

- Some configuration or autodetection is b0rked and detects TV out when it shouldn't, see Bug #134365

Re the fix, I think avoiding XRRGetScreenResources (as gtk+2) did is only a workaround, not a solution. It would only hide the actual bug, namely something disconnecting CRTCs-in-use.

Upgraded 8.04 to 8.10 on an Acer Extensa 3100 laptop with 915/910-based graphics. After logging into KDE 4 I've got the same repeated flickering of the internal LCD display every ten seconds until I disabled KDE4's "detect RandR (monitor) changes". As described above, manually calling XRandR command line tools causes flickering while the driver tries to detect which displays are currently connected.

Matthias: One more thing to consider, according to https://bugs.freedesktop.org/show_bug.cgi?id=16224 : "If I'm not mistaken, EDID transfers are done in-band and thus will cause the monitor to lose sync. There's really no way around it. From the recent thread
on the mailing list, it sounds like the solution is to fix GTK to not rely so heavily on calls to XRRGetScreenResources()."

Disabling TV out did not fix the problem for me. Disabling KDE's randr service did, though obviously this may not be the correct solution.

Jari Laamanen (yartsa) wrote :

Like Terry, I was also affected by this bug in the form of jerking of video playback every 10 sec. (or, jerking of konqueror auto-scrolling). Affected video driver was "intel", and the chip

00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)

Since I don't have a physical tv-out connector in my laptop, I disabled the "monitor-TV" in the xorg.conf, which cured this issue for me.

Laura (clarinette411) wrote :

Thanks to ilowman and dipsol. It's a temporary fix and it flickers when KDE is booting up, but at least it's not doing it all the time now.

Bryce Harrington (bryce) wrote :

Hi crwl,

Please attach the output of `lspci -vvnn`, and attach your /var/log/Xorg.0.log file from after reproducing this issue. If you've made any customizations to your /etc/X11/xorg.conf please attach that as well.

Changed in xserver-xorg-video-radeonhd:
status: New → Incomplete

Same problem here, ilowman and dipsol's fix work.

I would describe it as flickering though, it's more like every 10 sec. or so the mode of the monitor is changed. I think the randrmonitor module queries the VGA port every time which results in the "flickering". For example, if I run xrandr (from shell) without options to see what is connected, I get the same result.

Adriaan Leijnse (aidy-) wrote :

Same problem here, but killing kded4 doesn't help, neither does disabling the xrandr service. Instead, I found out that killing krunner works to fix the problem, but then I'm left without the program launcher.

Jakob Petsovits (jpetso) wrote :

I did not get flickers but mouse jumps (and video playback stutters, most probably similar to jartsa's comment above) on an i945. Discovered the relation to this bug while writing (and researching) https://bugs.launchpad.net/ubuntu/+source/kubuntu-meta/+bug/296481 - which also suggests that the timespan is an exact 10 seconds - there must be a corresponding timer in the KRandR kded service which triggers that XRRGetScreenResources call mentioned by Tormod Volden above.

Let's see if I'm able to do something about that...

Jakob Petsovits (jpetso) wrote :

You know, I'm really pissed. That KRandR kded module (aka "Detecting RANDR (monitor) changes") is *not* in KDE proper but only in an obviously unfinished working branch of the KWin lead developer, Lubos Lunak. See http://websvn.kde.org/branches/work/~seli/randr/module/?revision=864812 for the current location and contents of that code.

Congrats to Kubuntu for including unreleased code that explicitely specifies critical sections as "HACK", well done. The last commit (6 weeks ago) even disabled that timer, quote:

(...)
#if 0 // xrandr apparently can't detect hw changes and on some systems polling freezes X :(
    QTimer* timer = new QTimer( this );
    timer->start( 10000 ); // 10 s
    connect( timer, SIGNAL( timeout()), this, SLOT( poll()));
#endif
(...)

I suggest you people update the package to current SVN and leave it with that for Intrepid, so that not more damage is done than has already been inflicted. It won't work for events that happen during a KDE session then, but at least it doesn't break lots of systems in various subtle and annoying ways. Guess there's a reason that Lubos didn't include this into standard KDE packages yet.

Ofer Cohen (oc666) wrote :

Hey
I disabled the randr detecting, but my screen still blinking.
My screen blinking only after moving the mouse or press the keyboard.

David Tolnem (david-tolnem) wrote :

I have the exact same problem as oc666. I run a dual monitor setup on a Radeon HD 3600. I've disabled RANDR, which didn't help. Like for oc666, my blinking only happens on keyboard input.

After reading through the comments here I tried killing krunner, and in the ten minutes of typing I've been doing since then I can confirm that there has been no blinking whatsoever.

Folkert (f-boonstra) wrote :

Disabling the RANDR service worked for my Radeon9600.
In what situation would I need to enable it again?
Iow what is the exact purpose of that service?

Jakob Petsovits (jpetso) wrote :

The purpose of that service is to recognize when new video outputs are being connected, and to call
xrandr --output $yourNewVideoOutput --auto
when that happens, i.e. to automatically enable the monitors that you connect.
You would want to enable it again when manually configuring your display(s) is not sufficient for you.

Changed in meta-kde:
status: Confirmed → Triaged
Changed in kdelibs:
status: New → Unknown
Ofer Cohen (oc666) wrote :

Killing krunner works for me.

Changed in kdelibs:
status: Unknown → New
Rob Munsch (munsch) wrote :

Confirmed. Flicker / partial screen redraw every 10 seconds. Did not occur on login screen. I notice once in KDE4 that i can see part of the login screen's background is what's being redrawn...

Disabling randr stopped it immediately.
Intel Mobile 915GM/GMS/910GML (rev 03)
on a Dell Inspiron 6000.

Changed in kdelibs:
status: New → Invalid
Jonathan Thomas (echidnaman) wrote :

This problem has been determined to be caused by the SuSE xrandr 1.2 patch we and SuSE are using. In KDE 4.2 we have Kephal which should be able to replace the patch.

Changed in kdebase-workspace:
milestone: none → ubuntu-9.04
status: Triaged → Fix Committed
Changed in xserver-xorg-video-radeonhd:
status: Incomplete → Invalid
Alexander (lxndr82) wrote :

I had the same problem after upgrade to 8.10 Kubuntu. Disabling that service did not work, killing kde4d did not work. Eventually killing krunner having service disabled did the trick!
My hardware is (old): 01:00.0 VGA compatible controller [0300]: Silicon Integrated Systems [SiS] 65x/M650/740 PCI/AGP VGA Display Adapter [1039:6325].
At least it looks slick :-)

Alienation (miguel-andrade) wrote :

I confirm killing krunner ( $>pkill krunner ) stops the flikering.

Jonathan Thomas (echidnaman) wrote :

KDE 4.2 beta1 has been released to Kubuntu Jaunty. Packages for Intrepid are available for Kubuntu Intrepid via the kubuntu-experimental personal package archive for those interested in testing/using them.

Changed in kdebase-workspace:
status: Fix Committed → Fix Released
Bernhard (b.a.koenig) wrote :

Is the flickering issue resolved in 4.2?

Jonathan Thomas (echidnaman) wrote :

Yes. The polling daemon no longer exists and was replaced with a better tool. (See comment #57)

Ofer Cohen (oc666) wrote :

I just upgrade to kde 4.2 with the next guide:
http://www.kubuntu.org/node/58#instructions

But the problem still occur.

z_mikowski (z-mikowski) wrote :

Found same problem on fresh install of intrepid, all packages updated as of 20081216 20:00 PST

mmikowski@logic:~$ lspci |grep 965
00:00.0 Host bridge: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)

Confirmed fixed per https://bugs.launchpad.net/ubuntu/+source/meta-kde/+bug/278471/comments/37 ( have a DVI output which also showed LVDS, one on top the other. Later I removed the XRandr service as also suggested above.

What a thoroughly frustrating bug :(

Moe (english-editing) wrote :

Kde 4.1 I think this is a driver problem, so try this: Applications>System>Hardware drivers; a hardware drivers window should now appear. If one or more accelerated graphics drivers, which have not been activated, appear, then activate the only one or the recommended one. You need this driver for desktop effects. This should get rid of the flicker.

Well I still have krunner in kde4.2 and no kephal (or am I missing something??)
It is a problem 4.2 packaging from http://ppa.launchpad.net/kubuntu-experimental/ubuntu
To sum up, I have to pkill krunner in 4.2 to kill this bug.

I just tried jaunty alpha 3 and no longer see this bug.

David Roberts (david.roberts) wrote :

I can confirm that killing krunner fixes this, disabling KRandR does not. Also, the bug only seems to occur while the mouse is moving (screen blinks every ~3 seconds). In general it only blinks occasionally if the mouse is motionless, even if the keyboard is being used. After adding a script to ~/.kde/Autostart/ that executes `pkill krunner`, it now only seems to blink a few times while KDE is starting up.

Does anyone know what it is about krunner that causes this?

Also, this bug seems to be mainly about the KRandR issue. Should a separate bug be filed for the krunner issue?

David Tolnem (david-tolnem) wrote :

As mentioned before on this bug, I was having the krunner issue, but upgrading to KDE 4.2 has solved the problem for me. In two days of using it, there hasn't been a single blink.

David Tolnem (david-tolnem) wrote :

Actually, I was wrong. It still blinks, just a lot less than it used to.

D (dj-lp) wrote :

Same here. Became a *lot* better in KDE 4.2. You almost think it disappeared. But it's just down from 5 seconds to minutes. I hope this gets fixed completely before jaunty is released. I will try the pkill krunner workaround... But how could one live without krunner? ;)

Thomas Pilarski (thomas.pi) wrote :

I have noticed, that the following message is printed out, when this flickers begins.

CE: hpet increasing min_delta_ns to 15000 nsec

Are AMD uses affected by this problem? AFAIK: There is no hpet clocksource on am systems.

haarcuba (haarcuba) wrote :

Hi Everybody: I think there is a solution without killing krunner. When I killed krunner it did stop flickering, but on my machine there is also another way: just uncheck the "start automatically" box for the screen saver in the Desktop Settings (available via System Settings).

The flickering is gone and I can use krunner, yay!

For a screen saver, I use xscreensaver (I put it in an Autostart script).

Guys, this isn't a support or chat forum!

The cause and solution are well-known for more than 3 months now.
https://bugs.launchpad.net/ubuntu/+source/kdebase-workspace/+bug/278471/comments/41

Be sure to ALWAYS READ ALL COMMENTS AND ONLY EVER EVEN CONSIDER POSTING if
you have something really new that is related to the problem.

--
Matthias Andree

wwlytton (wwlytton) wrote :

Same problem using fvwm -- I have nothing kde or gnome running

problem is new with new clean full installation done yesterday (03-16-2009)

this is on an IBM X60 laptop

flicker also every 10 sec and Xorg.0.log reports as follows on each one:

(EE) intel(0): underrun on pipe B!

D (dj-lp) wrote :

Hi,

I've published a hotfix here:
http://linux-tipps.blogspot.com/2009/03/fixing-high-latency-with-kde4-display.html

Hope this helps, please report in the blog comments instead of here, to avoid the "chatting". ;)

Tanubi (taf-undying) wrote :

I have the flickering with the radeon driver, a Mobility FireGL 5200 and dual monitor setup.
The flickering was on latest intrepid (with backports repository) and still is there on an up-to-date jaunty.

I could correlate the flickering of my external monitor to screen activity.
When I do nothing, the screen flickers almost not at all.
When I move a window, or switch between virtual desktops, the screen flickers more often.
When I run glxgears, the monitor stays blank until I quit glxgears.

Also, disabling desktop effects improved my situation.

With radeonhd, the screen does not flicker at all. So maybe this is related to 3D acceleration?

Changed in kdelibs:
status: Invalid → Confirmed
savasten (savasten) on 2010-03-02
Changed in xserver-xorg-video-radeonhd (Ubuntu):
status: Invalid → Fix Released
Changed in kdelibs:
importance: Unknown → Medium
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