fixed cursor visibility update on show/hide_cursor commands for secondary head on NV40 architecture (hardware bug workaround). Confirmed Dualhead up and working correctly with two analog connected screens on PCIe 6600 GT.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11368 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/accelerants/nvidia/engine/nv_crtc2.c

@@ -1,6 +1,6 @@
 /* second CTRC functionality for GeForce cards */
 /* Author:
-   Rudolf Cornelissen 11/2002-1/2005
+   Rudolf Cornelissen 11/2002-2/2005
 */
 
 #define MODULE_BIT 0x00020000
@@ -682,6 +682,11 @@ status_t nv_crtc2_cursor_show()
 	/* b0 = 1 enables cursor */
 	CRTC2W(CURCTL0, (CRTC2R(CURCTL0) | 0x01));
 
+	/* workaround for hardware bug confirmed existing on NV43:
+	 * Cursor visibility is not updated without a position update if its hardware
+	 * retrace sync is enabled. */
+	if (si->ps.card_arch == NV40A) DAC2W(CURPOS, (DAC2R(CURPOS)));
+
 	return B_OK;
 }
 
@@ -695,6 +700,11 @@ status_t nv_crtc2_cursor_hide()
 	/* b0 = 0 disables cursor */
 	CRTC2W(CURCTL0, (CRTC2R(CURCTL0) & 0xfe));
 
+	/* workaround for hardware bug confirmed existing on NV43:
+	 * Cursor visibility is not updated without a position update if its hardware
+	 * retrace sync is enabled. */
+	if (si->ps.card_arch == NV40A) DAC2W(CURPOS, (DAC2R(CURPOS)));
+
 	return B_OK;
 }