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>

2 files changed, 94 insertions, 11 deletions

diff --git a/include/drm/drm.h b/include/drm/drm.h
index 0864c6920941..15e55039b7f1 100644
--- a/include/drm/drm.h
+++ b/include/drm/drm.h
@@ -454,6 +454,7 @@ struct drm_irq_busid {
 enum drm_vblank_seq_type {
         _DRM_VBLANK_ABSOLUTE = 0x0,     /**< Wait for specific vblank sequence number */
         _DRM_VBLANK_RELATIVE = 0x1,     /**< Wait for given number of vblanks */
+        _DRM_VBLANK_FLIP = 0x8000000,   /**< Scheduled buffer swap should flip */
         _DRM_VBLANK_NEXTONMISS = 0x10000000,    /**< If missed, wait for next vblank */
         _DRM_VBLANK_SECONDARY = 0x20000000,     /**< Secondary display controller */
         _DRM_VBLANK_SIGNAL = 0x40000000 /**< Send signal instead of blocking */
@@ -486,6 +487,19 @@ union drm_wait_vblank {
         struct drm_wait_vblank_reply reply;
 };
 
+#define _DRM_PRE_MODESET 1
+#define _DRM_POST_MODESET 2
+
+/**
+ * DRM_IOCTL_MODESET_CTL ioctl argument type
+ *
+ * \sa drmModesetCtl().
+ */
+struct drm_modeset_ctl {
+        uint32_t crtc;
+        uint32_t cmd;
+};
+
 /**
  * DRM_IOCTL_AGP_ENABLE ioctl argument type.
  *
@@ -570,6 +584,7 @@ struct drm_set_version {
 #define DRM_IOCTL_GET_CLIENT            DRM_IOWR(0x05, struct drm_client)
 #define DRM_IOCTL_GET_STATS             DRM_IOR( 0x06, struct drm_stats)
 #define DRM_IOCTL_SET_VERSION           DRM_IOWR(0x07, struct drm_set_version)
+#define DRM_IOCTL_MODESET_CTL           DRM_IOW(0x08, struct drm_modeset_ctl)
 
 #define DRM_IOCTL_SET_UNIQUE            DRM_IOW( 0x10, struct drm_unique)
 #define DRM_IOCTL_AUTH_MAGIC            DRM_IOW( 0x11, struct drm_auth)
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 1c1b13e29223..e79ce0781f0b 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -580,11 +580,54 @@ struct drm_driver {
         int (*kernel_context_switch) (struct drm_device *dev, int old,
                                       int new);
         void (*kernel_context_switch_unlock) (struct drm_device *dev);
-        int (*vblank_wait) (struct drm_device *dev, unsigned int *sequence);
-        int (*vblank_wait2) (struct drm_device *dev, unsigned int *sequence);
         int (*dri_library_name) (struct drm_device *dev, char *buf);
 
         /**
+         * get_vblank_counter - get raw hardware vblank counter
+         * @dev: DRM device
+         * @crtc: counter to fetch
+         *
+         * Driver callback for fetching a raw hardware vblank counter
+         * for @crtc.  If a device doesn't have a hardware counter, the
+         * driver can simply return the value of drm_vblank_count and
+         * make the enable_vblank() and disable_vblank() hooks into no-ops,
+         * leaving interrupts enabled at all times.
+         *
+         * Wraparound handling and loss of events due to modesetting is dealt
+         * with in the DRM core code.
+         *
+         * RETURNS
+         * Raw vblank counter value.
+         */
+        u32 (*get_vblank_counter) (struct drm_device *dev, int crtc);
+
+        /**
+         * enable_vblank - enable vblank interrupt events
+         * @dev: DRM device
+         * @crtc: which irq to enable
+         *
+         * Enable vblank interrupts for @crtc.  If the device doesn't have
+         * a hardware vblank counter, this routine should be a no-op, since
+         * interrupts will have to stay on to keep the count accurate.
+         *
+         * RETURNS
+         * Zero on success, appropriate errno if the given @crtc's vblank
+         * interrupt cannot be enabled.
+         */
+        int (*enable_vblank) (struct drm_device *dev, int crtc);
+
+        /**
+         * disable_vblank - disable vblank interrupt events
+         * @dev: DRM device
+         * @crtc: which irq to enable
+         *
+         * Disable vblank interrupts for @crtc.  If the device doesn't have
+         * a hardware vblank counter, this routine should be a no-op, since
+         * interrupts will have to stay on to keep the count accurate.
+         */
+        void (*disable_vblank) (struct drm_device *dev, int crtc);
+
+        /**
          * Called by \c drm_device_is_agp.  Typically used to determine if a
          * card is really attached to AGP or not.
          *
@@ -601,7 +644,7 @@ struct drm_driver {
 
         irqreturn_t(*irq_handler) (DRM_IRQ_ARGS);
         void (*irq_preinstall) (struct drm_device *dev);
-        void (*irq_postinstall) (struct drm_device *dev);
+        int (*irq_postinstall) (struct drm_device *dev);
         void (*irq_uninstall) (struct drm_device *dev);
         void (*reclaim_buffers) (struct drm_device *dev,
                                  struct drm_file * file_priv);
@@ -730,13 +773,28 @@ struct drm_device {
         /** \name VBLANK IRQ support */
         /*@{ */
 
-        wait_queue_head_t vbl_queue;    /**< VBLANK wait queue */
-        atomic_t vbl_received;
-        atomic_t vbl_received2;         /**< number of secondary VBLANK interrupts */
+        /*
+         * At load time, disabling the vblank interrupt won't be allowed since
+         * old clients may not call the modeset ioctl and therefore misbehave.
+         * Once the modeset ioctl *has* been called though, we can safely
+         * disable them when unused.
+         */
+        int vblank_disable_allowed;
+
+        wait_queue_head_t *vbl_queue;   /**< VBLANK wait queue */
+        atomic_t *_vblank_count;        /**< number of VBLANK interrupts (driver must alloc the right number of counters) */
         spinlock_t vbl_lock;
-        struct list_head vbl_sigs;              /**< signal list to send on VBLANK */
-        struct list_head vbl_sigs2;     /**< signals to send on secondary VBLANK */
-        unsigned int vbl_pending;
+        struct list_head *vbl_sigs;     /**< signal list to send on VBLANK */
+        atomic_t vbl_signal_pending;    /* number of signals pending on all crtcs*/
+        atomic_t *vblank_refcount;      /* number of users of vblank interruptsper crtc */
+        u32 *last_vblank;               /* protected by dev->vbl_lock, used */
+                                        /* for wraparound handling */
+        int *vblank_enabled;            /* so we don't call enable more than
+                                           once per disable */
+        int *vblank_inmodeset;          /* Display driver is setting mode */
+        struct timer_list vblank_disable_timer;
+
+        u32 max_vblank_count;           /**< size of vblank counter register */
         spinlock_t tasklet_lock;        /**< For drm_locked_tasklet */
         void (*locked_tasklet_func)(struct drm_device *dev);
 
@@ -757,6 +815,7 @@ struct drm_device {
         struct pci_controller *hose;
 #endif
         struct drm_sg_mem *sg;  /**< Scatter gather memory */
+        int num_crtcs;                  /**< Number of CRTCs on this device */
         void *dev_private;              /**< device private data */
         struct drm_sigdata sigdata;        /**< For block_all_signals */
         sigset_t sigmask;
@@ -990,10 +1049,19 @@ extern void drm_driver_irq_preinstall(struct drm_device *dev);
 extern void drm_driver_irq_postinstall(struct drm_device *dev);
 extern void drm_driver_irq_uninstall(struct drm_device *dev);
 
+extern int drm_vblank_init(struct drm_device *dev, int num_crtcs);
 extern int drm_wait_vblank(struct drm_device *dev, void *data,
-                           struct drm_file *file_priv);
+                           struct drm_file *filp);
 extern int drm_vblank_wait(struct drm_device *dev, unsigned int *vbl_seq);
-extern void drm_vbl_send_signals(struct drm_device *dev);
+extern void drm_locked_tasklet(struct drm_device *dev,
+                               void(*func)(struct drm_device *));
+extern u32 drm_vblank_count(struct drm_device *dev, int crtc);
+extern void drm_handle_vblank(struct drm_device *dev, int crtc);
+extern int drm_vblank_get(struct drm_device *dev, int crtc);
+extern void drm_vblank_put(struct drm_device *dev, int crtc);
+/* Modesetting support */
+extern int drm_modeset_ctl(struct drm_device *dev, void *data,
+                           struct drm_file *file_priv);
 extern void drm_locked_tasklet(struct drm_device *dev, void(*func)(struct drm_device*));
 
                                 /* AGP/GART support (drm_agpsupport.h) */