drm/vmwgfx: Make fence sequences continous across a VT switch.

A vt switch in stealth mode would take down the FIFO, and re-
initialize fence sequence numbers. This patch
saves the current state of the fence sequence when the FIFO is
disabled.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
index 01feb48..f7d5f70 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
@@ -98,8 +98,7 @@
 		 (unsigned int) min,
 		 (unsigned int) fifo->capabilities);
 
-	dev_priv->fence_seq = (uint32_t) -100;
-	dev_priv->last_read_sequence = (uint32_t) -100;
+	dev_priv->fence_seq = dev_priv->last_read_sequence;
 	iowrite32(dev_priv->last_read_sequence, fifo_mem + SVGA_FIFO_FENCE);
 
 	return vmw_fifo_send_fence(dev_priv, &dummy);