drm/vbl rework: rework how the drm deals with vblank.

Other Authors: Michel Dänzer <michel@tungstengraphics.com>
mga: Ian Romanick <idr@us.ibm.com>
via: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>

This re-works the DRM internals to provide a better interface for drivers
to expose vblank on multiple crtcs.

It also includes work done by Michel on making i915 triple buffering and pageflipping work properly.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/char/drm/mga_drv.h b/drivers/char/drm/mga_drv.h
index f6ebd24..8f7291f 100644
--- a/drivers/char/drm/mga_drv.h
+++ b/drivers/char/drm/mga_drv.h
@@ -120,6 +120,7 @@
 	u32 clear_cmd;
 	u32 maccess;
 
+	atomic_t vbl_received;		/**< Number of vblanks received. */
 	wait_queue_head_t fence_queue;
 	atomic_t last_fence_retired;
 	u32 next_fence_to_post;
@@ -181,11 +182,14 @@
 extern int mga_warp_init(drm_mga_private_t * dev_priv);
 
 				/* mga_irq.c */
+extern int mga_enable_vblank(struct drm_device *dev, int crtc);
+extern void mga_disable_vblank(struct drm_device *dev, int crtc);
+extern u32 mga_get_vblank_counter(struct drm_device *dev, int crtc);
 extern int mga_driver_fence_wait(struct drm_device * dev, unsigned int *sequence);
 extern int mga_driver_vblank_wait(struct drm_device * dev, unsigned int *sequence);
 extern irqreturn_t mga_driver_irq_handler(DRM_IRQ_ARGS);
 extern void mga_driver_irq_preinstall(struct drm_device * dev);
-extern void mga_driver_irq_postinstall(struct drm_device * dev);
+extern int mga_driver_irq_postinstall(struct drm_device * dev);
 extern void mga_driver_irq_uninstall(struct drm_device * dev);
 extern long mga_compat_ioctl(struct file *filp, unsigned int cmd,
 			     unsigned long arg);