Tearing after using xrandr with xf86-video-ati

[darklegion]

I put this here because I'm using a number of ebuilds from overlays so I wasn't sure if I could put it in one of the main subforums.

Anyway, if I make any sort of change using xrandr e.g. switching resolution or switching to portrait mode (don't have such a setup but I checked it anyway), then I'll get screen tearing from thereafter, even if I switch back to the original configuration. It doesn't matter if vsync is on or off, and it happens with both opengl apps and also 2D apps run through Compton twith vsync enabled. If I restart X, the problem is gone until I have to make a change again.

I've tested with both SwapBuffersWait on and off.

The issue doesn't occur with the nvidia binary drivers on my desktop.

Hardware and software specifications:

Asus N56DP with A10-4600M (laptop with a Trinity APU)
Mesa-9999
Linux-3.14-rc1
xf86-video-ati-9999
xrandr/libXrandr 1.4.2
xorg-server-9999
libdrm-9999
llvm-9999


I think it may be related to this bug: https://bugs.freedesktop.org/show_bug.cgi?id=32789

I can workaround this by running these apps that need resolution changes in a separate X server but it's a bit of an awkward configuration.

Thanks for any help