drm/i915: Kill vblank waits after pipe enable on gmch platforms

The pipe might not start to actually run until the port has been enabled
(depends on the platform and port type). So don't try to wait for vblank
after we enabled the pipe but haven't yet enabled the port.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
References: https://bugs.freedesktop.org/show_bug.cgi?id=77297
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -4500,7 +4500,6 @@ static void valleyview_modeset_global_resources(struct drm_device *dev)
 static void valleyview_crtc_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_encoder *encoder;
 	int pipe = intel_crtc->pipe;
@@ -4536,7 +4535,6 @@ static void valleyview_crtc_enable(struct drm_crtc *crtc)
 
 	intel_update_watermarks(crtc);
 	intel_enable_pipe(intel_crtc);
-	intel_wait_for_vblank(dev_priv->dev, pipe);
 	intel_set_cpu_fifo_underrun_reporting(dev, pipe, true);
 
 	for_each_encoder_on_crtc(dev, crtc, encoder)
@@ -4548,7 +4546,6 @@ static void valleyview_crtc_enable(struct drm_crtc *crtc)
 static void i9xx_crtc_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_encoder *encoder;
 	int pipe = intel_crtc->pipe;
@@ -4572,7 +4569,6 @@ static void i9xx_crtc_enable(struct drm_crtc *crtc)
 
 	intel_update_watermarks(crtc);
 	intel_enable_pipe(intel_crtc);
-	intel_wait_for_vblank(dev_priv->dev, pipe);
 	intel_set_cpu_fifo_underrun_reporting(dev, pipe, true);
 
 	for_each_encoder_on_crtc(dev, crtc, encoder)