drm/i915: apply G45 vblank count code to all G4x chips and fix max_frame_count

All G4x and newer chips use the new style frame count register, with a
full 32 bit frame count.  Update the code to reflect this.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_dma.c

@@ -1161,8 +1161,11 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 #endif
 
 	dev->driver->get_vblank_counter = i915_get_vblank_counter;
-	if (IS_GM45(dev))
+	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
+	if (IS_G4X(dev)) {
+		dev->max_vblank_count = 0xffffffff; /* full 32 bit counter */
 		dev->driver->get_vblank_counter = gm45_get_vblank_counter;
+	}
 
 	i915_gem_load(dev);
 

drivers/gpu/drm/i915/i915_irq.c

@@ -574,8 +574,6 @@ int i915_driver_irq_postinstall(struct drm_device *dev)
 
 	dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;
 
-	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
-
 	/* Unmask the interrupts that we always want on. */
 	dev_priv->irq_mask_reg = ~I915_INTERRUPT_ENABLE_FIX;