drm: Rework vblank-wait handling to allow interrupt reduction.

Previously, drivers supporting vblank interrupt waits would run the interrupt
all the time, or all the time that any 3d client was running, preventing the
CPU from sleeping for long when the system was otherwise idle.  Now, interrupts
are disabled any time that no client is waiting on a vblank event. The new
method uses vblank counters on the chipsets when the interrupts are turned
off, rather than counting interrupts, so that we can continue to present
accurate vblank numbers.

Co-author: Michel Dänzer <michel@tungstengraphics.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/mga/mga_drv.h b/drivers/gpu/drm/mga/mga_drv.h
index f6ebd24bd58..88257c276eb 100644
--- a/drivers/gpu/drm/mga/mga_drv.h
+++ b/drivers/gpu/drm/mga/mga_drv.h
@@ -120,6 +120,7 @@ typedef struct drm_mga_private {
         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_install_microcode(drm_mga_private_t * dev_priv);
 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);