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>

1 files changed, 51 insertions, 18 deletions

diff --git a/drivers/char/drm/mga_irq.c b/drivers/char/drm/mga_irq.c
index 9302cb8f0f83..06852fb4b278 100644
--- a/drivers/char/drm/mga_irq.c
+++ b/drivers/char/drm/mga_irq.c
@@ -35,6 +35,20 @@
 #include "mga_drm.h"
 #include "mga_drv.h"
 
+u32 mga_get_vblank_counter(struct drm_device *dev, int crtc)
+{
+        const drm_mga_private_t *const dev_priv =
+                (drm_mga_private_t *) dev->dev_private;
+
+        if (crtc != 0) {
+                return 0;
+        }
+
+
+        return atomic_read(&dev_priv->vbl_received);
+}
+
+
 irqreturn_t mga_driver_irq_handler(DRM_IRQ_ARGS)
 {
         struct drm_device *dev = (struct drm_device *) arg;
@@ -47,9 +61,8 @@ irqreturn_t mga_driver_irq_handler(DRM_IRQ_ARGS)
         /* VBLANK interrupt */
         if (status & MGA_VLINEPEN) {
                 MGA_WRITE(MGA_ICLEAR, MGA_VLINEICLR);
-                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);
                 handled = 1;
         }
 
@@ -78,22 +91,34 @@ irqreturn_t mga_driver_irq_handler(DRM_IRQ_ARGS)
         return IRQ_NONE;
 }
 
-int mga_driver_vblank_wait(struct drm_device * dev, unsigned int *sequence)
+int mga_enable_vblank(struct drm_device *dev, int crtc)
 {
-        unsigned int cur_vblank;
-        int ret = 0;
+        drm_mga_private_t *dev_priv = (drm_mga_private_t *) 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("tried to enable vblank on non-existent crtc %d\n",
+                          crtc);
+                return 0;
+        }
 
-        *sequence = cur_vblank;
+        MGA_WRITE(MGA_IEN, MGA_VLINEIEN | MGA_SOFTRAPEN);
+        return 0;
+}
 
-        return ret;
+
+void mga_disable_vblank(struct drm_device *dev, int crtc)
+{
+        if (crtc != 0) {
+                DRM_ERROR("tried to disable vblank on non-existent crtc %d\n",
+                          crtc);
+        }
+
+        /* Do *NOT* disable the vertical refresh interrupt.  MGA doesn't have
+         * a nice hardware counter that tracks the number of refreshes when
+         * the interrupt is disabled, and the kernel doesn't know the refresh
+         * rate to calculate an estimate.
+         */
+        /* MGA_WRITE(MGA_IEN, MGA_VLINEIEN | MGA_SOFTRAPEN); */
 }
 
 int mga_driver_fence_wait(struct drm_device * dev, unsigned int *sequence)
@@ -125,14 +150,22 @@ void mga_driver_irq_preinstall(struct drm_device * dev)
         MGA_WRITE(MGA_ICLEAR, ~0);
 }
 
-void mga_driver_irq_postinstall(struct drm_device * dev)
+int mga_driver_irq_postinstall(struct drm_device * dev)
 {
         drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
+        int ret;
+
+        ret = drm_vblank_init(dev, 1);
+        if (ret)
+                return ret;
 
         DRM_INIT_WAITQUEUE(&dev_priv->fence_queue);
 
-        /* Turn on vertical blank interrupt and soft trap interrupt. */
-        MGA_WRITE(MGA_IEN, MGA_VLINEIEN | MGA_SOFTRAPEN);
+        /* Turn on soft trap interrupt.  Vertical blank interrupts are enabled
+         * in mga_enable_vblank.
+         */
+        MGA_WRITE(MGA_IEN, MGA_SOFTRAPEN);
+        return 0;
 }
 
 void mga_driver_irq_uninstall(struct drm_device * dev)