Intel i915GM (xf86-video-intel modesetting) Tearing during playback with XV

Michel Dänzer michel at
Wed Feb 21 22:56:53 PST 2007

On Wed, 2007-02-21 at 14:47 -0800, Keith Packard wrote:
> On Wed, 2007-02-21 at 20:47 +0100, Lukas Hejtmanek wrote:
> > according to sources, G965 does not provide video overlay. It provides 
> > textured video only. (at least it does not setup adaptor for video overlay for
> > G965). Anyway, using xvinfo, can you see attributes like saturation or gamma
> > for any adaptor? If not, you are only using textured video thus you cannot
> > expect tearless video.
> Right, the G965 eliminated the overlay so the driver provides only
> textured video. It would be fairly easy to stick a spin loop into the
> server blocking for vretrace before painting a frame of video; I don't
> like to do that in general because of performance issues, but it might
> be worth a try to see if that eliminates the tearing issue.

I wonder if the support I added to the DRM recently for scheduling DRI
buffer swaps couldn't be used for this. Things might be more complicated
with a compositing manager though. Do we know whether the tearing is due
to the colourspace conversion blit or the compositing manager's reaction
to the damage event, or possibly even both?

Earthling Michel Dänzer           |
Libre software enthusiast         |          Debian, X and DRI developer

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