drm/i915: Drop pipe_enable checks in vblank funcs

With Ville's rework to use drm_crtc_vblank_on/off the core will take
care of rejecting drm_vblank_get calls when the pipe is off. Also the
core won't call the get_vblank_counter hooks in that case either. And
since we've dropped ums support recently we can now remove these
hacks, yay!

Noticed while trying to answer questions Laurent had about how the new
atomic helpers work.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/i915/i915_irq.c

@@ -492,31 +492,6 @@ static void i915_enable_asle_pipestat(struct drm_device *dev)
 	spin_unlock_irq(&dev_priv->irq_lock);
 }
 
-/**
- * i915_pipe_enabled - check if a pipe is enabled
- * @dev: DRM device
- * @pipe: pipe to check
- *
- * Reading certain registers when the pipe is disabled can hang the chip.
- * Use this routine to make sure the PLL is running and the pipe is active
- * before reading such registers if unsure.
- */
-static int
-i915_pipe_enabled(struct drm_device *dev, int pipe)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		/* Locking is horribly broken here, but whatever. */
-		struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
-		struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-
-		return intel_crtc->active;
-	} else {
-		return I915_READ(PIPECONF(pipe)) & PIPECONF_ENABLE;
-	}
-}
-
 /*
  * This timing diagram depicts the video signal in and
  * around the vertical blanking period.
@@ -583,12 +558,6 @@ static u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
 	unsigned long low_frame;
 	u32 high1, high2, low, pixel, vbl_start, hsync_start, htotal;
 
-	if (!i915_pipe_enabled(dev, pipe)) {
-		DRM_DEBUG_DRIVER("trying to get vblank count for disabled "
-				"pipe %c\n", pipe_name(pipe));
-		return 0;
-	}
-
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		struct intel_crtc *intel_crtc =
 			to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
@@ -648,12 +617,6 @@ static u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int reg = PIPE_FRMCOUNT_GM45(pipe);
 
-	if (!i915_pipe_enabled(dev, pipe)) {
-		DRM_DEBUG_DRIVER("trying to get vblank count for disabled "
-				 "pipe %c\n", pipe_name(pipe));
-		return 0;
-	}
-
 	return I915_READ(reg);
 }
 
@@ -2647,9 +2610,6 @@ static int i915_enable_vblank(struct drm_device *dev, int pipe)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 
-	if (!i915_pipe_enabled(dev, pipe))
-		return -EINVAL;
-
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	if (INTEL_INFO(dev)->gen >= 4)
 		i915_enable_pipestat(dev_priv, pipe,
@@ -2669,9 +2629,6 @@ static int ironlake_enable_vblank(struct drm_device *dev, int pipe)
 	uint32_t bit = (INTEL_INFO(dev)->gen >= 7) ? DE_PIPE_VBLANK_IVB(pipe) :
 						     DE_PIPE_VBLANK(pipe);
 
-	if (!i915_pipe_enabled(dev, pipe))
-		return -EINVAL;
-
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	ironlake_enable_display_irq(dev_priv, bit);
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
@@ -2684,9 +2641,6 @@ static int valleyview_enable_vblank(struct drm_device *dev, int pipe)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 
-	if (!i915_pipe_enabled(dev, pipe))
-		return -EINVAL;
-
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	i915_enable_pipestat(dev_priv, pipe,
 			     PIPE_START_VBLANK_INTERRUPT_STATUS);
@@ -2700,9 +2654,6 @@ static int gen8_enable_vblank(struct drm_device *dev, int pipe)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 
-	if (!i915_pipe_enabled(dev, pipe))
-		return -EINVAL;
-
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	dev_priv->de_irq_mask[pipe] &= ~GEN8_PIPE_VBLANK;
 	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);
@@ -2754,9 +2705,6 @@ static void gen8_disable_vblank(struct drm_device *dev, int pipe)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 
-	if (!i915_pipe_enabled(dev, pipe))
-		return;
-
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	dev_priv->de_irq_mask[pipe] |= GEN8_PIPE_VBLANK;
 	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);