Created attachment 98157 [details]
Please look into attached screenshot. What you see there is reproducible with enabled glamor and with ogl1/2/3/gles/xrender KWin compositing engine and without compositing. For some reason this glamor issue is KWin specific, there is no such artefacts with Compiz or Metacity.
Tested on Linux 3.11-3.14, Mesa 9.2-10.2 git (git1404271930.151a20), libglamor 0.5-0.6 git (git1403131830.a4fbc7), radeon driver 7.20-7.3.0 git (git1404160730.48d3db), X.Org Server 1.14-1.15.
Kubuntu 13.10-14.04 x86_64, KWin 4.11.0-4.11.8, Radeon HD 6620G.
Please attach your xorg log and dmesg output. Is this still and issue with a newer kernel or mesa?
> Please attach your xorg log and dmesg output.
> Is this still and issue with a newer kernel or mesa?
Yes, still issue with libdrm 2.4.54+git1405030630.5126fc, Mesa 10.3~git1405030730.64c467, radeon driver 7.3.99+git1405030730.be1469 and Linux 3.15rc3.
Created attachment 98364 [details]
Created attachment 98365 [details]
Not reproducible with X.Org Server 1.16.