Screen tearing at top of screen with VSync enabled on Compiz with fullscreen OpenGL programs

[Gareth Hart]

Binary package hint: compiz

I am noticing a problem when I have Sync to VBlank enabled for applications which involve OpenGL, particularly when in fullscreen. If there is consistent fast scrolling action at the very top of the screen, then screen tearing occurs there, a problem does not happen with Metacity, so I have concluded this is a problem with Compiz - I am using the non-free NVidia driver.

It happens on Wine applications as well as on native Linux applications as well, such as Gens GS and Google Earth, but doesn't occur on Firefox or Totem.

VSync to Blank is of course enabled on both the OpenGL section of NVidia settings and in CompizConfig Settings Manager.

NVidia settings tell me that my LCD monitor is currently using a refresh rate of 75.02Hz. Asking Compiz to detect the refresh rate causes Compiz to jerk along. Setting it to 75Hz (my monitor's refresh rate) and above causes the problem with screen tearing at the top of the screen. I did note that this problem from memory did not occur on Gutsy and Hardy, but occurs on Intrepid and Jaunty, which I am currently using.

What should happen:

No screen tearing occurs.

What happens instead:

Screen tearing occurs at the top of the screen during fast paced action on fullscreen OpenGL applications.

Output of lspci | grep -i vga:
01:00.0 VGA compatible controller: nVidia Corporation GeForce 8800 GT (rev a2)

ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
MachineType: System manufacturer System Product Name
NonfreeKernelModules: nvidia
Package: compiz 1:0.8.2-0ubuntu8.1
PackageArchitecture: all
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.30-020630rc3-generic root=UUID=3f23e463-0763-4534-b006-ec5880198328 ro vga=795 #GRUB_DISABLE_LINUX_UUID=true quiet quiet splash
ProcEnviron:
 LANG=C
 SHELL=/bin/bash
ProcVersionSignature: Error: [Errno 2] No such file or directory: '/proc/version_signature'
SourcePackage: compiz

[Youssef (that-y-guy)]

i can confirm this on ubuntu 9.04 using the provided nvidia diver (180) and also on driver version 185 !

If we set "unredirect fullscreen windows" on, the tearing on fullscreen stops completely. But this results in blinking whenever we right-click in the fullscreen app: the desktop shows and then re-disappears, and this is VERY annoying rendering the fullscreen experience an unbearable one.

If we set the option "unredirect fullscreen windows" off, the blinking stops completely but the tearing comes back in a horrible break line at the top of the screen.

[rbruce_mtl (robertbruce1977)]

This is still happening in Karmic... 9.10 using a GeForce 8800Ultra and the 185 drivers. Only the top 25% of the screen is affected as if vsync is only applied to the bottom 75%. I have tried all combinations of settings and it does not seem this there is a workaround.

Let me know how I can help.

[Travis Watkins (amaranth)]

Do this happen if you disable Sync to VBlank in compiz? If you have it enabled in the nvidia driver you do not need to enable it separately in compiz.

[Cezary Baginski (cezary0)]

I also had tearing and finally got rid of it.

I have:
 MCP78S [GeForce 8200]
 AMD Phenom(tm) II X4 940
 Ubuntu Karmic 9.10 with latest updates from proposed
 2.6.31-6-rt x86_64 kernel
 gnome + compiz

The fix:
- enable Sync to VBlank in nvidia-settings (opengl section), compiz
- restart compiz
- tearing stops in compiz (rotate cube) and video playback

The least tearing during H264 playback in mplayer is with '-vo gl' (not gl2, or xv, or x11).

I'll will maybe checkout ffmpeg-mt if it makes a difference on other video outputs - high cpu usage may also be the cause.

Would it makes sense to at least warn users about having sync to blank turned off?

[hepaly (hurezi)]

Same problem with gf 9300m
If I try use the 3D windows effect, and rotate the cube, then the motion is very slow, and the edge of the windows are tearing. It worked correctly with the last compiz update (0.8.3 20090917)
os: Ubuntu 9.10 karmic
hw: acer aspire 5720z

[hepaly (hurezi)]

I reinstalled the karmic rc (with clean install) and enabled restricted nvidia driver (in hw drivers menu). At this time, the compiz effects are working well. There is no screen tearing.
compiz settings:
detect_refresh_rate: disabled
refresh_rate: set to 60Hz by manualy

[j2snowden (j2snowden)]

I have this bug too. Is a f...g showstopper. Was ok with ccsm and vsync to blank in Jaunty but on Karmic its unfixable. No matter what you do you have this annoying tearing. Somebody fix this, please. Already watching vidoes on Window 7. Works like a charm. No tearing, excellent video quality, no interlace, image and video sharpening in nvdia drivers as well as colours. Works great, smooth, no bugs. Love it and goodby Ubuntu. 2 years is too much to deal with this things. You do not fix, somebody finds a fix and insted to fix it you make it impossibe for us to fix it. Great! Thats why people hate you. Thats why. loved Ubuntu, thought you'll be fixing bugs, making user experience better. Instead poeple can't even play vidoes normally. Just such a basic thing people do on their computers nowdays is broken by Canonical. I think nobody at Canonical tries to watch a single video on Ubuntu. They have Windowses for that and they don't care. Mr Shuttleworth have already admitted that Windows 7 is great. So why bother to make a new system, nobody is going to use. Event the maker. Its a joke. Go and buy Windows 7 as Mr. Shuttleworth and you will be fine. He doesn't use Ubuntu, why should you?? And thing about users and not programmers. Even developers can't fix this, so what a poor user can do? I know I'm back to Windows. Oh and one more thing: gery, brown and orange sucks!

[Travis Watkins (amaranth)]

This does not affect the release notes as the vsync option is not enabled by default and this has been an issue for some time now anyway.