vsync support in radeon? visual tearing
At the moment, my 2D acceleration in the radeon driver seems to work very well. However, I suffer from visual tearing. I notice it during video playback, my screensaver, dragging windows, everything. It's very unpleasant to the eye. If you aren't sure what this is or if it's happening to you then check out this page to learn about what I mean by tearing. Am I correct that this happens because there is no vsync support in the driver? Is there plans for fixing that in the future? Just wondering.
Last edited by surfer; 05-18-2008 at 09:32 PM.
As I understand, 2d vsync basically doesn't exist, except for Xv. I think it would be possible to implement, but as far as I know, no one has yet. However, I have noticed that the tearing is worse than could be accounted for from simple vsync issues. Is there anyone who can explain this?
(please excuse the double post)
Ah, but Xv seems not to be vsynced either. That should be done. Anyone?
Maybe I can look into this, although I've not had much success in comprehending the driver before. I don't have any experience writing drivers, and a graphics driver is a complex beast.
There is vsync support for 3D, but that's it at the moment. We haven't worked out all the infrastructural details for Xv and 2D yet. It's definitely an area where we could use more developers.
I may be wrong but even in the nvidia drivers there's no support for 2d syncing. I suffer from the same problem (although I have an nvidia graphics card) and have been looking for a solution.
The only "solution" I've found is to run compiz, because since it renders through opengl the drivers are able to sync. That's not really a viable solution for me though.
Most people have this problem but they don't really notice it, for me it really pisses me to see a window tear while I'm moving it. I wish I had the skills to solve this problem but I don't, and unfortunately I don't see a solution for this in the near future.
vsync for 3d is broken for me(compiz, tearings) with mesa git for last three weeks or so.
Originally Posted by agd5f
I have this problem too. I'm using the latest kernel, libdrm, mesa and xf86-video-ati from git.
Originally Posted by netkas
Don't you need 2.6.33 for 3D vsync to work? And doesn't radeon already have Xv "tear free" rendering? Or is that not the same as Xv vsync?
Xv has vsync, the problem is compositing. With compositing, it doesn't matter whether Xv or 3D has Vsync, you're going to get tearing anyway since the compositor is not VSynced.
DRI2 is supposed to fix this (DRI2 is enabled only with KMS with radeon), but I can't confirm that; kwin4 was tearing even with DRI2/KMS enabled.
Anyway, in full screen mode, VSync works (by default in KDE and with a setting in Compiz) since in full screen the compositor gets disabled.
For r6xx+. you need KMS and a drm with r6xx interrupt support to get vsynced GL (assuming the app uses the vsync GL mechanisms).