compiz team mailing list archive

[Da-fox <755841@xxxxxxxxxxxxxxxxxx>]

(In reply to comment #85)
> (In reply to comment #72)
> > Just as an update from the past post.
> 
> Thanks for the update!
> 
> > Unfortunately, all my attempts for fixing this properly have failed so far, the
> > hardware does not wants to collaborate with the software for inter-ring
> > synchronization.
> 
> I have a couple questions if you don't mind. In a previous comment, you
> mentioned that a fix would require work in the kernel, in libdrm and in the X
> driver. So is a fix really viable within the SNB product cycle? Does it affect
> Ivy Bridge as well? I ask because I may consider upgrading early to Ivy Bridge
> if this is no longer a issue.
> 
> > So the workaround I used previously still applies - I need to disable
> > compositing and use either vaapi or gl rendering, which perform vsync'ed screen
> > updates. This way, I see no tearing.
> 
> I can still see tearing with GL rendering. It's much less noticeable, but it's
> there. I can see it clearly when I'm watching basketball games in a 1080p TV
> (using HDMI), specially during the fastbreak, when the camera pans quickly. But
> yea, it's much better than X11, Xv or anything like that. Is this expected? I
> tested both with mplayer and VLC (glx output).
> 
You might be seeing the effect as shown in my attachment (https://bugs.freedesktop.org/attachment.cgi?id=47585), which according to daniel vetter is "probably unfixable". I think this is because possibly that is actually an artifact of capturing the screenshot. However something else which happens for me is that in the vertical-bars video the bars don't move smoothly across the screen. I don't know how to really explain it, but it is as if my screen has a really slow switching time, so that the front of the bars (as they move) lights up, while the rear fades out. However this fading is not gradual, but seems to happen with a lot of 'blinking'. I'm not sure what is causing this yet, but I think it might be some artifact of the screen (seems to happen with some bars painted in the gimp, too), it looks quite weird.
Anyway make sure it's none of that, take a picture with a (decent) camera.

> I can't even test VAAPI. VLC supports it, but when I enable it, I get 100% CPU
> usage and less than 1 FPS for some reason. There's the mplayer patches for
> VAAPI support, but it seems in very bad shape. Is there a test program for
> VAAPI?
You can try the mplayer-vaapi branch at git://gitorious.org/vaapi/mplayer.git , which is maintained by Gwenole Beauchesne, who also works on intel's vaapi support. The mplayer version it is based on is quite old, and it is based on the original mplayer (not mplayer2), but it works fine nonetheless.

> 
> For the record, I'm not running a composite manager.
> 
> Thanks for looking into this Eugeni.

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https://bugs.launchpad.net/bugs/755841

Title:
  [sandybridge] Graphics tearing when playing video

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