Try R300_SPAN_DISABLE_LOCKING env var if this hangs.
GL_RENDERER = Mesa DRI R300 20060815 AGP 1x x86/MMX+/3DNow!+/SSE TCL
rgba: 8 8 8 8
            basic #1 (0.2,0.2): 1.000000,1.000000,0.301961,0.200000   Delta: 0.800000,0.800000,0.001961,0.000000
            basic #2 (0.8,0.2): 1.000000,1.000000,0.376471,0.200000   Delta: 0.200000,0.800000,0.001471,0.000000
            basic #3 (0.8,0.8): 1.000000,1.000000,0.450980,0.200000   Delta: 0.200000,0.200000,0.000980,0.000000
            basic #4 (0.2,0.8): 1.000000,1.000000,0.376471,0.200000   Delta: 0.800000,0.200000,0.001471,0.000000
     tex2d scaled #1 (0.2,1.2): 0.600000,0.309804,0.403922,0.352941   Delta: -0.200000,0.109804,0.203922,0.152941
     tex2d scaled #2 (0.8,1.2): 0.396078,0.309804,0.607843,0.454902   Delta: 0.196078,0.109804,-0.192157,-0.045098
     tex2d scaled #3 (0.8,1.8): 0.396078,0.450980,0.607843,0.525490   Delta: 0.196078,-0.349020,-0.192157,-0.274510
     tex2d scaled #4 (0.2,1.8): 0.600000,0.450980,0.403922,0.423529   Delta: -0.200000,-0.349020,0.203922,-0.076471
          texrect #1 (1.2,0.2): 0.219608,0.780392,0.780392,0.780392   Delta: -0.310392,0.310392,0.700392,0.510392
          texrect #2 (1.8,0.2): 0.219608,0.780392,0.780392,0.780392   Delta: -0.070392,0.080392,0.700392,0.380392
          texrect #1 (1.8,0.8): 0.219608,0.780392,0.780392,0.780392   Delta: -0.070392,0.080392,0.470392,0.270392
          texrect #1 (1.2,0.8): 0.219608,0.780392,0.780392,0.780392   Delta: -0.310392,0.310392,0.470392,0.390392
   tex2d unscaled #1 (1.2,1.2): 1.000000,0.501961,0.501961,0.498039   Delta: 0.000000,0.001961,0.001961,-0.001961
   tex2d unscaled #2 (1.8,1.2): 1.000000,0.501961,0.501961,0.498039   Delta: 0.000000,0.001961,0.001961,-0.001961
   tex2d unscaled #3 (1.8,1.8): 1.000000,0.501961,0.501961,0.498039   Delta: 0.000000,0.001961,0.001961,-0.001961
   tex2d unscaled #4 (1.2,1.8): 1.000000,0.501961,0.501961,0.498039   Delta: 0.000000,0.001961,0.001961,-0.001961
Max delta: 0.800000