Created attachment 110136 [details]
Example screen shot with artifacts

Artifacts on the screen on notebook asus S301L.

The laptop has a muxless video card. I use DRI_PRIME.

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x76 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs:
3 outputs: 2 associated providers: 1 name:Intel
Provider 1: id: 0x51 cap: 0xf, Source Output, Sink Output, Source Offload, Sink
Offload crtcs: 2 outputs: 0 associated providers: 1 name:radeon


DRI_PRIME=1 LD_LIBRARY_PATH=/opt/mesa-master/lib/
LD_PRELOAD=/opt/mesa-master/lib/dri/radeonsi_dri.so glxgears

DRI_PRIME=1 LD_LIBRARY_PATH=/opt/mesa-master/lib/
LD_PRELOAD=/opt/mesa-master/lib/dri/radeonsi_dri.so amoeba


Example screen shot as an attachment amoeba.jpg

Uname:
Linux mj 3.17-1-amd64 #1 SMP Debian 3.17-1~exp1 (2014-10-14) x86_64 GNU/Linux