Running progs/openvg/trivial/arc i am receiving a segfault when i change the blend mode to VG_BLEND_DARKEN:
diff --git a/progs/openvg/trivial/arc.c b/progs/openvg/trivial/arc.c
index db686be..492ea38 100644
--- a/progs/openvg/trivial/arc.c
+++ b/progs/openvg/trivial/arc.c
@@ -51,7 +51,7 @@ init(void)
     vgSetPaint(vgPaint, VG_FILL_PATH);

     vgSeti(VG_RENDERING_QUALITY, VG_RENDERING_QUALITY_NONANTIALIASED);
-    vgSeti(VG_BLEND_MODE, VG_BLEND_SRC_OVER);
+    vgSeti(VG_BLEND_MODE, VG_BLEND_DARKEN);
     vgSetf(VG_STROKE_LINE_WIDTH, 2.0f);
     vgSeti(VG_STROKE_CAP_STYLE, VG_CAP_SQUARE);
     vgSeti(VG_STROKE_JOIN_STYLE, VG_JOIN_MITER);



Backtrace:

#0  0x0058d7f6 in get_sampler_varient (unit=0, sampler=0x80a8650, texture=0x0,
    processor=0) at sp_state_sampler.c:207
#1  0x0058da48 in softpipe_reset_sampler_varients (softpipe=0x8058750)
    at sp_state_sampler.c:263
#2  0x0058c85d in update_tgsi_samplers (softpipe=0x8058750) at sp_state_derived.c:201
#3  0x0058c9b8 in softpipe_update_derived (softpipe=0x8058750) at sp_state_derived.c:250
#4  0x0057eeba in softpipe_draw_range_elements (pipe=0x8058750, indexBuffer=0x0,
    indexSize=0, min_index=0, max_index=4294967295, mode=6, start=0, count=19)
    at sp_draw_arrays.c:128
#5  0x0057f0d5 in softpipe_draw_elements (pipe=0x8058750, indexBuffer=0x0, indexSize=0,
    mode=6, start=0, count=19) at sp_draw_arrays.c:191
#6  0x0057ee5c in softpipe_draw_arrays (pipe=0x8058750, mode=6, start=0, count=19)
    at sp_draw_arrays.c:104
#7  0x00ec7d47 in draw_polygon (ctx=0x8091390, poly=0x80b0200) at polygon.c:302
#8  0x00ec8445 in polygon_array_fill (polyarray=0x80ac724, ctx=0x8091390)
    at polygon.c:462
#9  0x00ed0438 in path_fill (p=0x80ac6f8, mat=0x8091968) at path.c:1565
#10 0x00ed037b in path_render (p=0x80ac6f8, paintModes=3) at path.c:1541
#11 0x00ebf172 in vgDrawPath (path=134924024, paintModes=3) at api_path.c:485
#12 0x0804924a in ellipse (vgPath=134924024, rx=4, ry=4, angle=0) at arc.c:35
#13 0x08049429 in draw () at arc.c:85
#14 0x08049bb0 in event_loop (dpy=0x804d008, win=16777218, egl_dpy=0x8056e10,
    egl_surf=0x80926a0) at eglcommon.c:171
#15 0x08049f43 in run (argc=1, argv=0xbffff3d4, init_f=0x8049250 <init>,
    resh_f=0x80493a3 <reshape>, draw_f=0x80493a8 <draw>, key_f=0) at eglcommon.c:275
#16 0x080496d4 in main (argc=1, argv=0xbffff3d4) at arc.c:137