[SOLVED] Bad rendering in kde4/qt4 with nvidia driver

elcore · 03-28-2015, 07:50 AM

So I've had this problem for quite some time, but only now I have found a way to snapshot.

Some random facts:

1. It happens on every driver I had tried, and also every kde4 release since 4.3
2. If the machine is booted with internal (radeon) card, there's no problem, only pci-e nvidia GT 440 is affected.
3. It's not just oxygen, it happens on any theme / decoration / widget style.
4. It happens with compositing and without compositing.

These random pixels appear at the top of the screen when compositing is off and logout menu is called.
To be precise, once the logout menu is cancelled and called again, then the entire top side of the screen is wrecked.

I have never seen anything like this in GTK, xfce4 works perfectly fine on the same machine.

No idea how to fix.

Image was taken from systemsettings / workspace appearance, the internal snapshot system somehow captured it.
Previously, I couldn't screenshot the problem, as it just wouldn't appear in ksnapshot or scrot.

image link

genss · 03-28-2015, 09:46 AM

nouveau or nvidia ?

dugan · 03-28-2015, 12:37 PM

I'd consider replacing the video card.

FTIO · 03-28-2015, 07:35 PM

You could also try this as user (it stops tearing):

Code:

nvidia-settings --assign CurrentMetaMode="VGA-0: 1600x900+0+0 { ForceCompositionPipeline = On }"

You can find the correct size of your 'vga' thing in the nvidia x server settings thing I think.

JackHair · 03-28-2015, 09:37 PM

You could try a LiveCD to check if you have the same problems there. If it's the same the cards RAM is probably gone.

elcore · 03-29-2015, 03:44 AM

Well, the chip works fine in win XP, win7 and xfce4.
This only happens on kde versions > 4.3 (I did pull the old IDE drive with old kde installed to check)

I always use the binary driver because nouveau never gets the resolution right.
That's 1680x1050_60 native and both nvidia and nouveau default to 1024x768 and call it native.
Probaby because my monitor doesn't provide any EDID and I have to manually specify DPI in xorg.conf.d
While the binary can load these values, I have never managed to get nouveau to work in native res.

device:

Code:

  Option       "NoLogo"               "True"
  Option       "MultiGPU"             "0"
  Option       "SLI"                  "0"
  Option       "Stereo"               "0"
  Option       "DPI"                  "91 x 91"
  Option       "ConnectToAcpid"       "off"
  Option       "UseEdidFreqs"         "FALSE"
  Option       "UseEdidDpi"           "FALSE"
  Option       "ModeValidation"       "NoEdidModes"
  Option       "ConnectedMonitor"     "CRT-0"
  Option       "UseDisplayDevice"     "CRT-0"
  Option       "IgnoreDisplayDevices" "DFP-0,DFP-1"
  Option       "TripleBuffer"         "True"

monitor:

Code:

Modeline       "1680x1050_60"  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync

I guess it would break other systems as well as GTK rendering if the video memory was corrupt.
What I thought it might be the cause is shared video memory from the board integrated card.
Not sure if it's possible that kde tries to use this extra memory somehow.

edit:

Seems it's oxygen engine "desktop theme" that's doing the logout thing, I have double checked this.
It does happen with some other themes, but not all of them.
Window decoration submenu only corrupts the oxygen preview when resizing the window, other previews are fine.
When Plastik is selected, it doesn't happen anywhere else except in that oxygen preview.
http://i.imgur.com/DujdyBH.png
http://i.imgur.com/kyyaFlL.png

edit II

Solved by kde upgrade, can't repro that bug on 4.14.6 from Alien Bob
Could be something in old qt that is used in 14.1, not quite sure about that.