[Intel-gfx] [PATCHv5] drm/i915: use waitqueue in wait for vblank

[Arun R Murthy]

Instead of using sleep functions in wait for vblank, which wakes up on
sleep timeout aften, thereby scheduler provoking scheduler. Hence use
waitqueue in wait for vblank.

Signed-off-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/i915/i915_dma.c      |    2 ++
 drivers/gpu/drm/i915/i915_drv.h      |    1 +
 drivers/gpu/drm/i915/i915_irq.c      |   17 +++++++++++++----
 drivers/gpu/drm/i915/intel_display.c |   10 ++++++----
 4 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 258b1be..896620c 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1506,6 +1506,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	mutex_init(&dev_priv->dpio_lock);
 	mutex_init(&dev_priv->modeset_restore_lock);
 
+	init_waitqueue_head(&dev_priv->wait_vblank);
+
 	intel_pm_setup(dev);
 
 	intel_display_crc_init(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 728b9c3..449bfef 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1590,6 +1590,7 @@ typedef struct drm_i915_private {
 	struct i915_dri1_state dri1;
 	/* Old ums support infrastructure, same warning applies. */
 	struct i915_ums_state ums;
+	wait_queue_head_t wait_vblank;
 } drm_i915_private_t;
 
 static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 56edff3..f97f0fe 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1513,8 +1513,11 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
 		for_each_pipe(pipe) {
-			if (pipe_stats[pipe] & PIPE_START_VBLANK_INTERRUPT_STATUS)
+			if (pipe_stats[pipe] &
+					PIPE_START_VBLANK_INTERRUPT_STATUS) {
 				drm_handle_vblank(dev, pipe);
+				wake_up_interruptible(&dev_priv->wait_vblank);
+			}
 
 			if (pipe_stats[pipe] & PLANE_FLIPDONE_INT_STATUS_VLV) {
 				intel_prepare_page_flip(dev, pipe);
@@ -3269,8 +3272,10 @@ static irqreturn_t i8xx_irq_handler(int irq, void *arg)
 				plane = !plane;
 
 			if (pipe_stats[pipe] & PIPE_VBLANK_INTERRUPT_STATUS &&
-			    i8xx_handle_vblank(dev, plane, pipe, iir))
+			    i8xx_handle_vblank(dev, plane, pipe, iir)) {
 				flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(plane);
+				wake_up_interruptible(&dev_priv->wait_vblank);
+			}
 
 			if (pipe_stats[pipe] & PIPE_CRC_DONE_INTERRUPT_STATUS)
 				i9xx_pipe_crc_irq_handler(dev, pipe);
@@ -3464,8 +3469,10 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 				plane = !plane;
 
 			if (pipe_stats[pipe] & PIPE_VBLANK_INTERRUPT_STATUS &&
-			    i915_handle_vblank(dev, plane, pipe, iir))
+			    i915_handle_vblank(dev, plane, pipe, iir)) {
 				flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(plane);
+				wake_up_interruptible(&dev_priv->wait_vblank);
+			}
 
 			if (pipe_stats[pipe] & PIPE_LEGACY_BLC_EVENT_STATUS)
 				blc_event = true;
@@ -3709,8 +3716,10 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 
 		for_each_pipe(pipe) {
 			if (pipe_stats[pipe] & PIPE_START_VBLANK_INTERRUPT_STATUS &&
-			    i915_handle_vblank(dev, pipe, pipe, iir))
+			    i915_handle_vblank(dev, pipe, pipe, iir)) {
 				flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(pipe);
+				wake_up_interruptible(&dev_priv->wait_vblank);
+			}
 
 			if (pipe_stats[pipe] & PIPE_LEGACY_BLC_EVENT_STATUS)
 				blc_event = true;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4d4a0d9..e1eb564 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -757,12 +757,14 @@ enum transcoder intel_pipe_to_cpu_transcoder(struct drm_i915_private *dev_priv,
 static void g4x_wait_for_vblank(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 frame, frame_reg = PIPE_FRMCOUNT_GM45(pipe);
+	u32 vblank_cnt;
 
-	frame = I915_READ(frame_reg);
+	vblank_cnt = drm_vblank_count(dev, pipe);
 
-	if (wait_for(I915_READ_NOTRACE(frame_reg) != frame, 50))
-		DRM_DEBUG_KMS("vblank wait timed out\n");
+	/* TODO: get the vblank time dynamically or from platform data */
+	wait_event_interruptible_timeout(dev_priv->wait_vblank,
+			(vblank_cnt != drm_vblank_count(dev, pipe)),
+			msecs_to_jiffies(16));
 }
 
 /**
-- 
1.7.9.5