[Intel-gfx] Add the support for IGDNG to disable VGA plane reliably

[Wang, Quanxian]

From: Wang, Quanxian <quanxian.wang at intel.com>

Add the support for IGDNG to disable VGA plane reliably(enhance commit db9f5915ce8121)
Also based on the spec, the sleep second should be 100us instead of 30us from IGDNG spec.

Signed-off-by: Wang, Quanxian <quanxian.wang at intel.com>

---
src/i830_display.c |    9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/i830_display.c b/src/i830_display.c
index 59ededc..6be624e 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1089,14 +1089,19 @@ i830_disable_vga_plane (xf86CrtcPtr crtc)
     OUTREG8(SRX, 1);
     sr01 = INREG8(SRX + 1);
     OUTREG8(SRX + 1, sr01 | (1 << 5));
-    usleep(30);
+    usleep(100);
     /* disable center mode on 965GM and G4X platform */
     if (IS_I965GM(pI830) || IS_G4X(pI830))
         vgacntrl &= ~(3 << 24);

     vgacntrl |= VGA_DISP_DISABLE;

-    OUTREG(VGACNTRL, vgacntrl);
+    if (IS_IGDNG(pI830))
+    {
+       OUTREG(CPU_VGACNTRL, vgacntrl);
+    } else {
+       OUTREG(VGACNTRL, vgacntrl);
+    }
     i830WaitForVblank(pScrn);

 }