Use programmable tap coefficients for (hopefully) better video image

    quality when downscaling. Remove unnecessary code programming the tap
    coefficients twice. Disable some code which is supposed to improve
    filtering quality but causes very visible image quality problems at
    least with rv250 when upscaling. Fix potentially broken FOURCC_RGB16T
    format (untested if it was broken, untested if it works now...). Change
    some magic numbers to (new) macro defines.

3 files changed, 46 insertions, 43 deletions

diff --git a/ChangeLog b/ChangeLog
index 22acadc..0a52cdd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2006-03-23  Roland Scheidegger  <rscheidegger_lists@hispeed.ch>
+	* src/radeon_reg.h:
+	* src/radeon_video.c: (RADEONResetVideo), (RADEONDisplayVideo),
+	(RADEONPutImage): Use programmable tap coefficients for (hopefully)
+	better video image quality when downscaling. Remove unnecessary code
+	programming the tap coefficients twice. Disable some code which is
+	supposed to improve filtering quality but causes very visible image
+	quality problems at least with rv250 when upscaling. Fix potentially
+	broken FOURCC_RGB16T format (untested if it was broken, untested if it
+	works now...). Change some magic numbers to (new) macro defines.
+
 2006-03-23  Benjamin Herrenschmidt  <benh@kernel.crashing.org>
 
 	* src/radeon_driver.c: (RADEONRestoreMode),
diff --git a/src/radeon_reg.h b/src/radeon_reg.h
index a18582d..53cc803 100644
--- a/src/radeon_reg.h
+++ b/src/radeon_reg.h
@@ -932,9 +932,13 @@
 #       define  RADEON_EXCL_VERT_START_MASK        0x000003ff
 #       define  RADEON_EXCL_VERT_END_MASK          0x03ff0000
 #define RADEON_OV0_FILTER_CNTL              0x04A0
-#       define FILTER_PROGRAMMABLE_COEF            0x00000000
-#       define FILTER_HARDCODED_COEF               0x0000000f
-#       define FILTER_COEF_MASK                    0x0000000f
+#       define RADEON_FILTER_PROGRAMMABLE_COEF            0x0
+#       define RADEON_FILTER_HC_COEF_HORZ_Y               0x1
+#       define RADEON_FILTER_HC_COEF_HORZ_UV              0x2
+#       define RADEON_FILTER_HC_COEF_VERT_Y               0x4
+#       define RADEON_FILTER_HC_COEF_VERT_UV              0x8
+#       define RADEON_FILTER_HARDCODED_COEF               0xf
+#       define RADEON_FILTER_COEF_MASK                    0xf
 
 #define RADEON_OV0_FOUR_TAP_COEF_0          0x04B0
 #define RADEON_OV0_FOUR_TAP_COEF_1          0x04B4
@@ -1023,10 +1027,12 @@
 #       define  RADEON_SCALER_SOURCE_YVYU422       0x00000C00L
 #       define  RADEON_SCALER_ADAPTIVE_DEINT       0x00001000L
 #       define  RADEON_SCALER_TEMPORAL_DEINT       0x00002000L
+#       define  RADEON_SCALER_CRTC_SEL             0x00004000L
 #       define  RADEON_SCALER_SMART_SWITCH         0x00008000L
 #       define  RADEON_SCALER_BURST_PER_PLANE      0x007F0000L
 #       define  RADEON_SCALER_DOUBLE_BUFFER        0x01000000L
 #       define  RADEON_SCALER_DIS_LIMIT            0x08000000L
+#       define  RADEON_SCALER_LIN_TRANS_BYPASS     0x10000000L
 #       define  RADEON_SCALER_INT_EMU              0x20000000L
 #       define  RADEON_SCALER_ENABLE               0x40000000L
 #       define  RADEON_SCALER_SOFT_RESET           0x80000000L
diff --git a/src/radeon_video.c b/src/radeon_video.c
index 3f44e4b..e11864c 100644
--- a/src/radeon_video.c
+++ b/src/radeon_video.c
@@ -1118,9 +1118,7 @@ RADEONResetVideo(ScrnInfoPtr pScrn)
     OUTREG(RADEON_OV0_SCALE_CNTL, RADEON_SCALER_SOFT_RESET);
     OUTREG(RADEON_OV0_AUTO_FLIP_CNTL, 0);   /* maybe */
     OUTREG(RADEON_OV0_EXCLUSIVE_HORZ, 0);
-    /* FIXME: we are not actually using the tap coefficients we program (twice!)? */
-    OUTREG(RADEON_OV0_FILTER_CNTL, FILTER_HARDCODED_COEF);
-    OUTREG(RADEON_OV0_FILTER_CNTL, 0x0000000f);
+    OUTREG(RADEON_OV0_FILTER_CNTL, RADEON_FILTER_PROGRAMMABLE_COEF);
     OUTREG(RADEON_OV0_KEY_CNTL, RADEON_GRAPHIC_KEY_FN_EQ |
 				RADEON_VIDEO_KEY_FN_FALSE |
 				RADEON_CMP_MIX_OR);
@@ -2535,12 +2533,17 @@ RADEONDisplayVideo(
     /* the only place it is documented in is in ATI source code */
     /* we need twice as much space for 4 tap filtering.. */
     /* under special circumstances turn on 4 tap filtering */
-    if(!is_rgb && (step_by_y==1) && (step_by_uv==1) && (h_inc < (1<<12)) && (deinterlacing_method!=METHOD_WEAVE) 
+    /* disable this code for now as it has a DISASTROUS effect on image quality when upscaling
+       at least on rv250 (only as long as the drw_w*2 <=... requirement is still met of course) */
+#if 0
+    if(!is_rgb && (step_by_y==1) && (step_by_uv==1) && (h_inc < (1<<12))
+       && (deinterlacing_method!=METHOD_WEAVE)
        && (drw_w*2 <= pPriv->overlay_scaler_buffer_width)){
         step_by_y=0;
         step_by_uv=1;
         h_inc_uv = h_inc;
         }
+#endif
 
     /* keep everything in 16.16 */
 
@@ -2575,18 +2578,7 @@ RADEONDisplayVideo(
     if (info->accelOn) RADEON_SYNC(info, pScrn);
     while(!(INREG(RADEON_OV0_REG_LOAD_CNTL) & RADEON_REG_LD_CTL_LOCK_READBACK));
 
-    dsr=(double)(1<<0xC)/h_inc;
-    if(dsr<0.25)dsr=0.25;
-    if(dsr>1.0)dsr=1.0;
-    tap_set=(int)((dsr-0.25)*100);
-    for(i=0;i<5;i++){
-	    OUTREG(RADEON_OV0_FOUR_TAP_COEF_0+i*4, (TapCoeffs[tap_set].coeff[i][0] &0xf) | 
-	    	((TapCoeffs[tap_set].coeff[i][1] &0x7f)<<8) | 
-	    	((TapCoeffs[tap_set].coeff[i][2] &0x7f)<<16) | 
-	    	((TapCoeffs[tap_set].coeff[i][3] &0xf)<<24));
-		}
-
-    RADEONWaitForFifo(pScrn, 14);
+    RADEONWaitForFifo(pScrn, 10);
     OUTREG(RADEON_OV0_H_INC, h_inc | ((h_inc_uv >> 1) << 16));
     OUTREG(RADEON_OV0_STEP_BY, step_by_y | (step_by_uv << 8));
 
@@ -2625,7 +2617,7 @@ RADEONDisplayVideo(
                                       ((dstBox->y1*y_mult) << 16)));
         OUTREG(RADEON_OV1_Y_X_END,   ((dstBox->x2 + x_off) |
                                       ((dstBox->y2*y_mult) << 16)));
-        scaler_src = (1 << 14);
+        scaler_src = RADEON_SCALER_CRTC_SEL;
     } else {
 	OUTREG(RADEON_OV0_Y_X_START, ((dstBox->x1 + x_off) |
 				      (((dstBox->y1*y_mult) + y_off) << 16)));
@@ -2634,7 +2626,9 @@ RADEONDisplayVideo(
 	scaler_src = 0;
     }
 
-
+    /* program the tap coefficients for better downscaling quality.
+       Could do slightly better by using hardcoded coefficients for one axis
+       in case only the other axis is downscaled (see RADEON_OV0_FILTER_CNTL) */
     dsr=(double)(1<<0xC)/h_inc;
     if(dsr<0.25)dsr=0.25;
     if(dsr>1.0)dsr=1.0;
@@ -2671,31 +2665,26 @@ RADEONDisplayVideo(
         | RADEON_SCALER_ENABLE | RADEON_SCALER_SMART_SWITCH | (0x7f<<16) | scaler_src;
    switch(id){
         case FOURCC_UYVY:
-                OUTREG(RADEON_OV0_SCALE_CNTL, RADEON_SCALER_SOURCE_YVYU422 | scale_cntl);
-                break;
+		scale_cntl |= RADEON_SCALER_SOURCE_YVYU422;
         case FOURCC_RGB24:
         case FOURCC_RGBA32:
-                OUTREG(RADEON_OV0_SCALE_CNTL, RADEON_SCALER_SOURCE_32BPP | scale_cntl | 0x10000000);
-                break;
-        case FOURCC_RGBT16:
-                OUTREG(RADEON_OV0_SCALE_CNTL, RADEON_SCALER_SOURCE_16BPP 
-                        | 0x10000000 
-                        | scale_cntl);
-                break;
+		scale_cntl |= RADEON_SCALER_SOURCE_32BPP | RADEON_SCALER_LIN_TRANS_BYPASS;
+		break;
         case FOURCC_RGB16:
-                OUTREG(RADEON_OV0_SCALE_CNTL, RADEON_SCALER_SOURCE_16BPP 
-                        | 0x10000000 
-                        | scale_cntl);
-                break;
+		scale_cntl |= RADEON_SCALER_SOURCE_16BPP | RADEON_SCALER_LIN_TRANS_BYPASS;
+		break;
+        case FOURCC_RGBT16:
+		scale_cntl |= RADEON_SCALER_SOURCE_15BPP | RADEON_SCALER_LIN_TRANS_BYPASS;
+		break;
         case FOURCC_YUY2:
         case FOURCC_YV12:
         case FOURCC_I420:
         default:
-                OUTREG(RADEON_OV0_SCALE_CNTL,  RADEON_SCALER_SOURCE_VYUY422 
-                        | ((info->ChipFamily>=CHIP_FAMILY_R200) ? RADEON_SCALER_TEMPORAL_DEINT :0) 
-                        | scale_cntl);
-        }
-
+		scale_cntl |= RADEON_SCALER_SOURCE_VYUY422
+			| ((info->ChipFamily >= CHIP_FAMILY_R200) ? RADEON_SCALER_TEMPORAL_DEINT : 0);
+		break;
+    }
+    OUTREG(RADEON_OV0_SCALE_CNTL, scale_cntl);
     OUTREG(RADEON_OV0_REG_LOAD_CNTL, 0);
 }
 
@@ -2785,11 +2774,8 @@ RADEONPutImage(
    	dstPitch=(width*4+0x0f)&(~0x0f);
 	srcPitch=width*4;
 	break;
-   case FOURCC_RGBT16:
-   	dstPitch=(width*2+0x0f)&(~0x0f);
-	srcPitch=(width*2+3)&(~0x03);
-	break;
    case FOURCC_RGB16:
+   case FOURCC_RGBT16:
    	dstPitch=(width*2+0x0f)&(~0x0f);
 	srcPitch=(width*2+3)&(~0x03);
 	break;