[PATCH 22/22] drm/i915: Add debug print for flip queue length

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Print some information on how many flips are in the queue waiting for
the GPU. There's no limit on the queue length currently.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |    1 +
 drivers/gpu/drm/i915/intel_atomic.c |    4 ++++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 87f5cba..5c089b2 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -892,6 +892,7 @@ typedef struct drm_i915_private {
 		struct work_struct work;
 		struct workqueue_struct *wq;
 		unsigned int next_flip_seq;
+		unsigned int queue_len;
 	} flip;
 } drm_i915_private_t;
 
diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
index d3aa566..d7cc978 100644
--- a/drivers/gpu/drm/i915/intel_atomic.c
+++ b/drivers/gpu/drm/i915/intel_atomic.c
@@ -2106,6 +2106,7 @@ static void intel_atomic_postpone_flip(struct drm_device *dev,
 	intel_flip->busy = ring != NULL;
 
 	list_move_tail(&intel_flip->base.list, &dev_priv->flip.list);
+	dev_priv->flip.queue_len++;
 
 	if (!ring)
 		return;
@@ -2186,6 +2187,7 @@ static void intel_atomic_process_flips_work(struct work_struct *work)
 				if (intel_flip->flip_seq != flip_seq)
 					break;
 				list_move_tail(&intel_flip->base.list, &flips);
+				dev_priv->flip.queue_len--;
 			}
 		}
 
@@ -2197,6 +2199,8 @@ static void intel_atomic_process_flips_work(struct work_struct *work)
 		mutex_lock(&dev->mode_config.mutex);
 		intel_atomic_schedule_flips(dev_priv, intel_crtc, &flips);
 		mutex_unlock(&dev->mode_config.mutex);
+
+		DRM_DEBUG_KMS("flip queue length = %u\n", dev_priv->flip.queue_len);
 	}
 }
 
-- 
1.7.8.6