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>

3 files changed, 57 insertions, 38 deletions

diff --git a/drivers/gpu/drm/r128/r128_drv.c b/drivers/gpu/drm/r128/r128_drv.c
index 6108e75..3265d53 100644
--- a/drivers/gpu/drm/r128/r128_drv.c
+++ b/drivers/gpu/drm/r128/r128_drv.c
@@ -43,12 +43,13 @@ static struct pci_device_id pciidlist[] = {
 static struct drm_driver driver = {
 	.driver_features =
 	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_PCI_DMA | DRIVER_SG |
-	    DRIVER_HAVE_DMA | DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED |
-	    DRIVER_IRQ_VBL,
+	    DRIVER_HAVE_DMA | DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED,
 	.dev_priv_size = sizeof(drm_r128_buf_priv_t),
 	.preclose = r128_driver_preclose,
 	.lastclose = r128_driver_lastclose,
-	.vblank_wait = r128_driver_vblank_wait,
+	.get_vblank_counter = r128_get_vblank_counter,
+	.enable_vblank = r128_enable_vblank,
+	.disable_vblank = r128_disable_vblank,
 	.irq_preinstall = r128_driver_irq_preinstall,
 	.irq_postinstall = r128_driver_irq_postinstall,
 	.irq_uninstall = r128_driver_irq_uninstall,
@@ -59,21 +60,20 @@ static struct drm_driver driver = {
 	.ioctls = r128_ioctls,
 	.dma_ioctl = r128_cce_buffers,
 	.fops = {
-		 .owner = THIS_MODULE,
-		 .open = drm_open,
-		 .release = drm_release,
-		 .ioctl = drm_ioctl,
-		 .mmap = drm_mmap,
-		 .poll = drm_poll,
-		 .fasync = drm_fasync,
+		.owner = THIS_MODULE,
+		.open = drm_open,
+		.release = drm_release,
+		.ioctl = drm_ioctl,
+		.mmap = drm_mmap,
+		.poll = drm_poll,
+		.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
-		 .compat_ioctl = r128_compat_ioctl,
+		.compat_ioctl = r128_compat_ioctl,
 #endif
 	},
-
 	.pci_driver = {
-		 .name = DRIVER_NAME,
-		 .id_table = pciidlist,
+		.name = DRIVER_NAME,
+		.id_table = pciidlist,
 	},
 
 	.name = DRIVER_NAME,
@@ -87,6 +87,7 @@ static struct drm_driver driver = {
 static int __init r128_init(void)
 {
 	driver.num_ioctls = r128_max_ioctl;
+
 	return drm_init(&driver);
 }
 
diff --git a/drivers/gpu/drm/r128/r128_drv.h b/drivers/gpu/drm/r128/r128_drv.h
index 011105e..5898b27 100644
--- a/drivers/gpu/drm/r128/r128_drv.h
+++ b/drivers/gpu/drm/r128/r128_drv.h
@@ -29,7 +29,7 @@
  *    Rickard E. (Rik) Faith <faith@valinux.com>
  *    Kevin E. Martin <martin@valinux.com>
  *    Gareth Hughes <gareth@valinux.com>
- *    Michel Dänzer <daenzerm@student.ethz.ch>
+ *    Michel D�zer <daenzerm@student.ethz.ch>
  */
 
 #ifndef __R128_DRV_H__
@@ -97,6 +97,8 @@ typedef struct drm_r128_private {
 	u32 crtc_offset;
 	u32 crtc_offset_cntl;
 
+	atomic_t vbl_received;
+
 	u32 color_fmt;
 	unsigned int front_offset;
 	unsigned int front_pitch;
@@ -149,11 +151,12 @@ extern int r128_wait_ring(drm_r128_private_t * dev_priv, int n);
 extern int r128_do_cce_idle(drm_r128_private_t * dev_priv);
 extern int r128_do_cleanup_cce(struct drm_device * dev);
 
-extern int r128_driver_vblank_wait(struct drm_device * dev, unsigned int *sequence);
-
+extern int r128_enable_vblank(struct drm_device *dev, int crtc);
+extern void r128_disable_vblank(struct drm_device *dev, int crtc);
+extern u32 r128_get_vblank_counter(struct drm_device *dev, int crtc);
 extern irqreturn_t r128_driver_irq_handler(DRM_IRQ_ARGS);
 extern void r128_driver_irq_preinstall(struct drm_device * dev);
-extern void r128_driver_irq_postinstall(struct drm_device * dev);
+extern int r128_driver_irq_postinstall(struct drm_device *dev);
 extern void r128_driver_irq_uninstall(struct drm_device * dev);
 extern void r128_driver_lastclose(struct drm_device * dev);
 extern void r128_driver_preclose(struct drm_device * dev,
diff --git a/drivers/gpu/drm/r128/r128_irq.c b/drivers/gpu/drm/r128/r128_irq.c
index c76fdca..d734901 100644
--- a/drivers/gpu/drm/r128/r128_irq.c
+++ b/drivers/gpu/drm/r128/r128_irq.c
@@ -35,6 +35,16 @@
 #include "r128_drm.h"
 #include "r128_drv.h"
 
+u32 r128_get_vblank_counter(struct drm_device *dev, int crtc)
+{
+	const drm_r128_private_t *dev_priv = dev->dev_private;
+
+	if (crtc != 0)
+		return 0;
+
+	return atomic_read(&dev_priv->vbl_received);
+}
+
 irqreturn_t r128_driver_irq_handler(DRM_IRQ_ARGS)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
@@ -46,30 +56,38 @@ irqreturn_t r128_driver_irq_handler(DRM_IRQ_ARGS)
 	/* VBLANK interrupt */
 	if (status & R128_CRTC_VBLANK_INT) {
 		R128_WRITE(R128_GEN_INT_STATUS, R128_CRTC_VBLANK_INT_AK);
-		atomic_inc(&dev->vbl_received);
-		DRM_WAKEUP(&dev->vbl_queue);
-		drm_vbl_send_signals(dev);
+		atomic_inc(&dev_priv->vbl_received);
+		drm_handle_vblank(dev, 0);
 		return IRQ_HANDLED;
 	}
 	return IRQ_NONE;
 }
 
-int r128_driver_vblank_wait(struct drm_device * dev, unsigned int *sequence)
+int r128_enable_vblank(struct drm_device *dev, int crtc)
 {
-	unsigned int cur_vblank;
-	int ret = 0;
+	drm_r128_private_t *dev_priv = dev->dev_private;
 
-	/* Assume that the user has missed the current sequence number
-	 * by about a day rather than she wants to wait for years
-	 * using vertical blanks...
-	 */
-	DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
-		    (((cur_vblank = atomic_read(&dev->vbl_received))
-		      - *sequence) <= (1 << 23)));
+	if (crtc != 0) {
+		DRM_ERROR("%s:  bad crtc %d\n", __func__, crtc);
+		return -EINVAL;
+	}
 
-	*sequence = cur_vblank;
+	R128_WRITE(R128_GEN_INT_CNTL, R128_CRTC_VBLANK_INT_EN);
+	return 0;
+}
+
+void r128_disable_vblank(struct drm_device *dev, int crtc)
+{
+	if (crtc != 0)
+		DRM_ERROR("%s:  bad crtc %d\n", __func__, crtc);
 
-	return ret;
+	/*
+	 * FIXME: implement proper interrupt disable by using the vblank
+	 * counter register (if available)
+	 *
+	 * R128_WRITE(R128_GEN_INT_CNTL,
+	 *            R128_READ(R128_GEN_INT_CNTL) & ~R128_CRTC_VBLANK_INT_EN);
+	 */
 }
 
 void r128_driver_irq_preinstall(struct drm_device * dev)
@@ -82,12 +100,9 @@ void r128_driver_irq_preinstall(struct drm_device * dev)
 	R128_WRITE(R128_GEN_INT_STATUS, R128_CRTC_VBLANK_INT_AK);
 }
 
-void r128_driver_irq_postinstall(struct drm_device * dev)
+int r128_driver_irq_postinstall(struct drm_device *dev)
 {
-	drm_r128_private_t *dev_priv = (drm_r128_private_t *) dev->dev_private;
-
-	/* Turn on VBL interrupt */
-	R128_WRITE(R128_GEN_INT_CNTL, R128_CRTC_VBLANK_INT_EN);
+	return drm_vblank_init(dev, 1);
 }
 
 void r128_driver_irq_uninstall(struct drm_device * dev)