Intel Linux Driver Still Working To Address Tearing

[ChrisXY]

Hm, old thread.

I actually have tearfree disabled, but use kwin's "fullscreen repaint" vsync with opengl compositing with one laptop display and one DVI/HDMI display and I don't see any tearing with this setup at all.

But it's still not really stable, I have been getting random hangs for months.

[drm] stuck on render ring
[drm] GPU HANG: ecode 0:0xf5f7fffe, in kwin [26522], reason: Ring hung, action: reset
[drm] Enabling RC6 states: RC6 on, RC6p on, RC6pp off

But mostly it recovers fine after a few seconds. Only sometimes it's hanging the chromium gpu process and I have to restart chromium...

[chrisb]

TearFree works correctly with multiple monitors, rotated, transformed, cloned or just extended. As always, you need to be using recent drivers to avoid bugs, and in particular you should be using at least 2.99.908, and I have been working on optimising TearFree itself just last week (by reducing the required copies for tracking damage). debian testing is not tracking the relevant bug fixes for SNA / TearFree.

Thanks, I didn't realise that Debian was so far behind. Good to know that it works. I tried Ubuntu and Firefox seems much better.

Suppose the user has a modern distribution (recent kernel+Intel drivers), and does not set TearFree, do you know which compositors (if any) will still do multi-monitor without tearing on an Intel GPU? I often see people recommending Compton with some particular vsync option, and it looks like xfwm4 git now has a wait_vblank() function which does

 ioctl (screen_info->dri_fd, DRM_IOCTL_WAIT_VBLANK, &vblank);

And I have also seen people recommending environment variables like

__GL_YIELD="USLEEP"

Does any of this work? Or perhaps work but synced to only one monitor? Is Unity/Gnome Shell/Kwin now tear free even without the TearFree option (since afaik they all have OpenGL compositors)?

I do not mind using TearFree since I do not do any intensive graphics work, but I am curious what the current state of play is - the list ("1. Not using a compositor or the application (for Xv, DRI apps) itself requests tearing.2. Not using SNA 3. Not using a kernel >= 3.8 4. vsync disabled through xorg.conf") suggests that most people now should be tear free by default as long as they use Gnome, Unity, or KDE? Are there still any important apps that default to request tearing?

[bwat47]

What is the required combination of kernel/desktop/compositor/appconfig to eliminate tearing on a multiple monitor setup? Can it be done? Is there any page flipping compositor that properly supports multiple monitors?

I have "TearFree" enabled in the Intel driver, and I still see tearing when dragging windows around in both Gnome and XFCE (with XFWM/Compton). My main complaint is that tearing is very noticeable when scrolling a page up and down in Firefox/Iceweasel. I do not get the message "Kernel page flipping support detected, enabling" in Xorg log, is that still relevant? I am using Debian Testing, SNA and TearFree are enabled in xorg.conf, Ivybridge i5 laptop HD4000 graphics with triple external DVI monitors connected via passive 1x HDMI>DVI and 2x DP>DVI cables.



This does not seem to make any difference.

Probably just an issue with your compton settings, its been a while since I used compton, but I recall you could set it up to use opengl + full page-flipping for total tear-free on intel. I'll see if I can dig up the settings I used to use.

[bwat47]

I have "TearFree" enabled in the Intel driver, and I still see tearing when dragging windows around in both Gnome and XFCE (with XFWM/Compton).

ugh, I love phoronix's ridiculous 5 minute edit limit, anyway this in your compton config file should give totally tear-free output on intel, using full opengl page-flipping:

backend = "glx";
paint-on-overlay = true;
glx-no-stencil = true;
glx-no-rebind-pixmap = true;
vsync = "opengl-swc";

the bolded ones are the most important. first one enables opengl backend for compton, other one tells it to use the page-flipping vsync method.

I had written a bit of a guide on this a while back: http://ubuntuforums.org/showthread.php?t=2144468

[chrisb]

ugh, I love phoronix's ridiculous 5 minute edit limit, anyway this in your compton config file should give totally tear-free output on intel, using full opengl page-flipping:



the bolded ones are the most important. first one enables opengl backend for compton, other one tells it to use the page-flipping vsync method.

I had written a bit of a guide on this a while back: http://ubuntuforums.org/showthread.php?t=2144468

I had those options already (are they the defaults?). I just tested again and I still get tearing on all three monitors (Iceweasel on XFCE / Debian Testing). I wish Debian wasn't so far behind with their Intel drivers.