diff --git a/src/i830_debug.c b/src/i830_debug.c
index 8f8ef9b..b252c3f 100644
--- a/src/i830_debug.c
+++ b/src/i830_debug.c
@@ -192,6 +192,8 @@ DEBUGSTRING(i830_debug_dpll)
 	    p1 = ffs((val & DPLL_FPA01_P1_POST_DIV_MASK_I830_LVDS) >>
 		     DPLL_FPA01_P1_POST_DIV_SHIFT);
 	    p2 = 14;
+	    if ((INREG(LVDS) & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP)
+		p2 = 7;
 	} else {
 	    mode = "DAC/serial";
 	    if (val & PLL_P1_DIVIDE_BY_TWO) {
@@ -689,6 +691,19 @@ void i830DumpRegs (ScrnInfoPtr pScrn)
 		xf86DrvMsg (pScrn->scrnIndex, X_WARNING, "p1 out of range\n");
 		break;
 	    }
+	    
+	    switch ((dpll >> 13) & 0x3) {
+	    case 0:
+		ref = 96000;
+		break;
+	    case 3:
+		ref = 100000;
+		break;
+	    default:
+		ref = 0;
+		xf86DrvMsg (pScrn->scrnIndex, X_WARNING, "ref out of range\n");
+		break;
+	    }
 	}
 	else
 	{
@@ -726,18 +741,19 @@ void i830DumpRegs (ScrnInfoPtr pScrn)
 		else
 		    p1 = ((dpll >> 16) & 0x3f) + 2;
 	    }
-	}
-	switch ((dpll >> 13) & 0x3) {
-	case 0:
-	    ref = 96000;
-	    break;
-	case 3:
-	    ref = 100000;
-	    break;
-	default:
-	    ref = 0;
-	    xf86DrvMsg (pScrn->scrnIndex, X_WARNING, "ref out of range\n");
-	    break;
+
+	    switch ((dpll >> 13) & 0x3) {
+	    case 0:
+		ref = 48000;
+		break;
+	    case 3:
+		ref = 66000;
+		break;
+	    default:
+		ref = 0;
+		xf86DrvMsg (pScrn->scrnIndex, X_WARNING, "ref out of range\n");
+		break;
+	    }
 	}
 	if (IS_I965G(pI830)) {
 	    phase = (dpll >> 9) & 0xf;
diff --git a/src/i830_display.c b/src/i830_display.c
index d16871d..6a71bbb 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1623,6 +1623,9 @@ i830_crtc_clock_get(ScrnInfoPtr pScrn, xf86CrtcPtr crtc)
 	    clock.p1 = ffs((dpll & DPLL_FPA01_P1_POST_DIV_MASK_I830_LVDS) >>
 			   DPLL_FPA01_P1_POST_DIV_SHIFT);
 	    clock.p2 = 14;
+	    /* if LVDS is dual-channel, then p2 = 7 */
+	    if ((INREG(LVDS) & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP)
+		clock.p2 = 7;
 
 	    if ((dpll & PLL_REF_INPUT_MASK) == PLLB_REF_INPUT_SPREADSPECTRUMIN)
 		i8xx_clock(66000, &clock); /* XXX: might not be 66MHz */