radeon: Use indirect register access for (un)hiding the cursor.

From:  <michel@tungstengraphics.com>

This avoids hangs that occur when touching these registers while the card is
busy with some cards.
---

 src/radeon_cursor.c |   35 ++++++++++++++++++++++++-----------
 1 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/radeon_cursor.c b/src/radeon_cursor.c
index f19f2bc..b8cfffd 100644
--- a/src/radeon_cursor.c
+++ b/src/radeon_cursor.c
@@ -98,12 +98,19 @@ radeon_crtc_show_cursor (xf86CrtcPtr crtc)
     RADEONInfoPtr      info       = RADEONPTR(pScrn);
     unsigned char     *RADEONMMIO = info->MMIO;
 
-    if (crtc_id == 0) 
-	OUTREGP(RADEON_CRTC_GEN_CNTL, RADEON_CRTC_CUR_EN | 2 << 20, 
-		~(RADEON_CRTC_CUR_EN | RADEON_CRTC_CUR_MODE_MASK));
-    else if (crtc_id == 1)
-	OUTREGP(RADEON_CRTC2_GEN_CNTL, RADEON_CRTC2_CUR_EN | 2 << 20,
-		~(RADEON_CRTC2_CUR_EN | RADEON_CRTC2_CUR_MODE_MASK));
+    switch (crtc_id) {
+    case 0:
+	OUTREG(RADEON_MM_INDEX, RADEON_CRTC_GEN_CNTL);
+	break;
+    case 1:
+	OUTREG(RADEON_MM_INDEX, RADEON_CRTC2_GEN_CNTL);
+	break;
+    default:
+	return;
+    }
+
+    OUTREGP(RADEON_MM_DATA, RADEON_CRTC_CUR_EN | 2 << 20, 
+	    ~(RADEON_CRTC_CUR_EN | RADEON_CRTC_CUR_MODE_MASK));
 }
 
 void
@@ -115,12 +122,18 @@ radeon_crtc_hide_cursor (xf86CrtcPtr crtc)
     RADEONInfoPtr      info       = RADEONPTR(pScrn);
     unsigned char     *RADEONMMIO = info->MMIO;
 
-    if (crtc_id == 0)
-	OUTREGP(RADEON_CRTC_GEN_CNTL, 0, ~RADEON_CRTC_CUR_EN);
-    else if (crtc_id == 1)
-	OUTREGP(RADEON_CRTC2_GEN_CNTL, 0, ~RADEON_CRTC2_CUR_EN);
-
+    switch (crtc_id) {
+    case 0:
+	OUTREG(RADEON_MM_INDEX, RADEON_CRTC_GEN_CNTL);
+	break;
+    case 1:
+	OUTREG(RADEON_MM_INDEX, RADEON_CRTC2_GEN_CNTL);
+	break;
+    default:
+	return;
+    }
 
+    OUTREGP(RADEON_MM_DATA, 0, ~RADEON_CRTC_CUR_EN);
 }
 
 void