From 3f17567e639293e5a03e4a2ec26f86abad31a9c9 Mon Sep 17 00:00:00 2001
From: Rudolf Cornelissen <rudolf.cornelissen@gmail.com>
Date: Wed, 9 Feb 2005 18:08:03 +0000
Subject: [PATCH] reverting to software retrace-sync for cursor position
 updates on pre-GeForce cards: it turns out there's no hardware sync here
 after all.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11299 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../accelerants/nvidia/engine/nv_crtc.c       | 44 ++++++++++++++++---
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/src/add-ons/accelerants/nvidia/engine/nv_crtc.c b/src/add-ons/accelerants/nvidia/engine/nv_crtc.c
index 36db20cf21..2b820e03ac 100644
--- a/src/add-ons/accelerants/nvidia/engine/nv_crtc.c
+++ b/src/add-ons/accelerants/nvidia/engine/nv_crtc.c
@@ -1,6 +1,6 @@
 /* CTRC functionality */
 /* Author:
-   Rudolf Cornelissen 11/2002-1/2005
+   Rudolf Cornelissen 11/2002-2/2005
 */
 
 #define MODULE_BIT 0x00040000
@@ -701,9 +701,8 @@ status_t nv_crtc_cursor_init()
 	/* select 32x32 pixel, 16bit color cursorbitmap, no doublescan */
 	NV_REG32(NV32_CURCONF) = 0x02000100;
 
-	/* activate hardware-sync between cursor updates and vertical retrace */
-	/* note:
-	 * on pre-NV10 cards hardware sync is hardwired ON */
+	/* activate hardware-sync between cursor updates and vertical retrace where
+	 * available */
 	if (si->ps.card_arch >= NV10A)
 		DACW(NV10_CURSYNC, (DACR(NV10_CURSYNC) | 0x02000000));
 
@@ -806,7 +805,42 @@ status_t nv_crtc_cursor_define(uint8* andMask,uint8* xorMask)
 /* position the cursor */
 status_t nv_crtc_cursor_position(uint16 x, uint16 y)
 {
-	/* the cursor position is updated during retrace by card hardware */
+	/* the cursor position is updated during retrace by card hardware except for
+	 * pre-GeForce cards */
+	if (si->ps.card_arch < NV10A)
+	{
+		uint16 yhigh;
+
+		/* make sure we are beyond the first line of the cursorbitmap being drawn during
+		 * updating the position to prevent distortions: no double buffering feature */
+		/* Note:
+		 * we need to return as quick as possible or some apps will exhibit lagging.. */
+
+		/* read the old cursor Y position */
+		yhigh = ((DACR(CURPOS) & 0x0fff0000) >> 16);
+		/* make sure we will wait until we are below both the old and new Y position:
+		 * visible cursorbitmap drawing needs to be done at least... */
+		if (y > yhigh) yhigh = y;
+
+		if (yhigh < (si->dm.timing.v_display - 16))
+		{
+			/* we have vertical lines below old and new cursorposition to spare. So we
+			 * update the cursor postion 'mid-screen', but below that area. */
+			while (((uint16)(NV_REG32(NV32_RASTER) & 0x000007ff)) < (yhigh + 16))
+			{
+				snooze(10);
+			}
+		}
+		else
+		{
+			/* no room to spare, just wait for retrace (is relatively slow) */
+			while ((NV_REG32(NV32_RASTER) & 0x000007ff) < si->dm.timing.v_display)
+			{
+				/* don't snooze much longer or retrace might get missed! */
+				snooze(10);
+			}
+		}
+	}
 
 	/* update cursorposition */
 	DACW(CURPOS, ((x & 0x0fff) | ((y & 0x0fff) << 16)));