r200: Fix lod bias correction.

glean/pointSprite shows that rv280 is trying to read from better
quality mipmap level. We have to correct default lod bias to match
required texture selection.

src/mesa/drivers/dri/r200/r200_reg.h

@@ -950,6 +950,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define     R200_TEXCOORD_ZERO                        (7  << 16)
 #define     R200_TEXCOORD_MASK                        (7  << 16)
 #define     R200_LOD_BIAS_MASK                        (0xfff80000)
+#define     R200_LOD_BIAS_FIXED_ONE                   (0x08000000)
+#define     R200_LOD_BIAS_CORRECTION                  (0x00600000)
 #define     R200_LOD_BIAS_SHIFT                       19
 #define R200_PP_TXSIZE_0                  0x2c0c /* NPOT only */
 #define R200_PP_TX_WIDTHMASK_SHIFT 0

src/mesa/drivers/dri/r200/r200_state_init.c

@@ -1386,7 +1386,7 @@ void r200InitState( r200ContextPtr rmesa )
       rmesa->hw.tex[i].cmd[TEX_PP_BORDER_COLOR] = 0;
       rmesa->hw.tex[i].cmd[TEX_PP_TXFORMAT_X] =
          (/* R200_TEXCOORD_PROJ | */
-          0x100000);	/* Small default bias */
+          R200_LOD_BIAS_CORRECTION);	/* Small default bias */
       if (rmesa->radeon.radeonScreen->drmSupportsFragShader) {
 	 rmesa->hw.tex[i].cmd[TEX_PP_TXOFFSET_NEWDRM] =
 	     rmesa->radeon.radeonScreen->texOffset[RADEON_LOCAL_TEX_HEAP];

src/mesa/drivers/dri/r200/r200_tex.c

@@ -324,18 +324,19 @@ static void r200TexEnv( GLcontext *ctx, GLenum target,
    case GL_TEXTURE_LOD_BIAS_EXT: {
       GLfloat bias, min;
       GLuint b;
-      const int fixed_one = 0x8000000;
+      const int fixed_one = R200_LOD_BIAS_FIXED_ONE;
 
       /* The R200's LOD bias is a signed 2's complement value with a
        * range of -16.0 <= bias < 16.0. 
        *
        * NOTE: Add a small bias to the bias for conform mipsel.c test.
        */
-      bias = *param + .01;
+      bias = *param;
       min = driQueryOptionb (&rmesa->radeon.optionCache, "no_neg_lod_bias") ?
 	  0.0 : -16.0;
       bias = CLAMP( bias, min, 16.0 );
-      b = (int)(bias * fixed_one) & R200_LOD_BIAS_MASK;
+      b = ((int)(bias * fixed_one)
+		+ R200_LOD_BIAS_CORRECTION) & R200_LOD_BIAS_MASK;
       
       if ( (rmesa->hw.tex[unit].cmd[TEX_PP_TXFORMAT_X] & R200_LOD_BIAS_MASK) != b ) {
 	 R200_STATECHANGE( rmesa, tex[unit] );