Comment 32 for bug 1043575

It looks like (per Alex Oranges previous comment) the fix for this issue is already submitted and commited to the master branch of xserver

See "2014-10-27 fb: Fix Bresenham algorithms for commonly used small segments."

http://cgit.freedesktop.org/xorg/xserver/log/

It was not applied to the 1.16 branch (nor am I sure how to request it be offically applied).

I'll try and research more into that workflow when I can. Until then you can either manually patch and build the package or wait until the patch is applied by maintainers.