Kubuntu Linux 14.04 64 bits (Kernel 4.2.0-7-generic)
Genius EasyPen i405 (UC-Logic WP5540U)
Broken: 2.73a,nuildbot 9c916b0, master
Short description of error
I've noticed this problem when I tried the new feature curve draw from master. But the problem also happen with texture paint. I have not been able to verify whether this also occurs with grease pencil. Having pressure sensitivity enabled, the stroke is erratic (it is choppy, dotted lines appear). The problem is most evident when you draw slow strokes. If you draw fast strokes, the problem is less frequent. In the file that I share I tested with texture paint, curve draw and grease pencil. To your left are the strokes drawn slowly. To the right, fast strokes.
The graphic tablet is a Genius EasyPen i405 (UC-Logic WP5540U) using evdev through this generic driver:
The problem does not occur in Windows with Blender.
GIMP on linux apparently works well with pressure sensitivity enabled .
Exact steps for others to reproduce the error
Draw with my graphics tablet in linux with pressure sensitivity enabled :)