[PATCH v2 08/16] drm/i915: Split watermark programming into pre and post steps

[ville.syrjala@linux.intel.com]

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

We need to perform watermark programming before and after changing the
plane configuration. Add two new vfuncs to do that. The pre phase is
supposed to switch over to the intermediate watermarks which are
computed so that they can deal with both the old and new plane
configurations. The post phase will arm the vblank based update
systems to switch over to the optimal target watermarks after the
plane configuration has for sure changed.

v2: Pass around intel_crtc and s/intel_crtc/crtc/

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |  5 +++
 drivers/gpu/drm/i915/intel_drv.h | 11 +++++
 drivers/gpu/drm/i915/intel_pm.c  | 88 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c90d5ac..d4f8ae8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -407,6 +407,7 @@ struct intel_plane_config;
 struct intel_crtc;
 struct intel_limit;
 struct dpll;
+struct intel_crtc_wm_config;
 
 struct drm_i915_display_funcs {
 	bool (*fbc_enabled)(struct drm_device *dev);
@@ -437,6 +438,10 @@ struct drm_i915_display_funcs {
 				 struct drm_crtc *crtc,
 				 uint32_t sprite_width, int pixel_size,
 				 bool enable, bool scaled);
+	void (*program_wm_pre)(struct intel_crtc *crtc,
+			       const struct intel_crtc_wm_config *config);
+	void (*program_wm_post)(struct intel_crtc *crtc,
+				const struct intel_crtc_wm_config *config);
 	void (*modeset_global_resources)(struct drm_device *dev);
 	/* Returns the active state of the crtc, and if the crtc is active,
 	 * fills out the pipe-config with the hw state. */
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 72f01b1..4b59be3 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -358,6 +358,13 @@ struct intel_pipe_wm {
 	bool sprites_scaled;
 };
 
+struct intel_crtc_wm_config {
+	/* target watermarks for the pipe */
+	struct intel_pipe_wm target;
+	/* intermediate watermarks for pending/active->target transition */
+	struct intel_pipe_wm intm;
+};
+
 struct intel_crtc {
 	struct drm_crtc base;
 	enum pipe pipe;
@@ -1001,6 +1008,10 @@ void intel_init_runtime_pm(struct drm_i915_private *dev_priv);
 void intel_fini_runtime_pm(struct drm_i915_private *dev_priv);
 void ilk_wm_get_hw_state(struct drm_device *dev);
 void ilk_update_pipe_wm(struct drm_device *dev, enum pipe pipe);
+void intel_program_watermarks_pre(struct intel_crtc *crtc,
+				  const struct intel_crtc_wm_config *config);
+void intel_program_watermarks_post(struct intel_crtc *crtc,
+				   const struct intel_crtc_wm_config *config);
 
 
 /* intel_sdvo.c */
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6fc6416..ccf920a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2950,6 +2950,20 @@ void ilk_update_pipe_wm(struct drm_device *dev, enum pipe pipe)
 	spin_unlock(&crtc->wm.lock);
 }
 
+static void ilk_wm_cancel(struct intel_crtc *crtc)
+{
+	struct drm_device *dev = crtc->base.dev;
+
+	assert_spin_locked(&crtc->wm.lock);
+
+	crtc->wm.dirty = false;
+
+	if (crtc->wm.vblank) {
+		drm_vblank_put(dev, crtc->pipe);
+		crtc->wm.vblank = false;
+	}
+}
+
 static void ilk_update_sprite_wm(struct drm_plane *plane,
 				     struct drm_crtc *crtc,
 				     uint32_t sprite_width, int pixel_size,
@@ -3084,6 +3098,24 @@ void intel_update_sprite_watermarks(struct drm_plane *plane,
 						   pixel_size, enabled, scaled);
 }
 
+void intel_program_watermarks_pre(struct intel_crtc *crtc,
+				  const struct intel_crtc_wm_config *config)
+{
+	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
+
+	if (dev_priv->display.program_wm_pre)
+		dev_priv->display.program_wm_pre(crtc, config);
+}
+
+void intel_program_watermarks_post(struct intel_crtc *crtc,
+				   const struct intel_crtc_wm_config *config)
+{
+	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
+
+	if (dev_priv->display.program_wm_post)
+		dev_priv->display.program_wm_post(crtc, config);
+}
+
 static struct drm_i915_gem_object *
 intel_alloc_context_page(struct drm_device *dev)
 {
@@ -6522,6 +6554,60 @@ void intel_fini_runtime_pm(struct drm_i915_private *dev_priv)
 	pm_runtime_disable(device);
 }
 
+static void ilk_program_wm_pre(struct intel_crtc *crtc,
+			       const struct intel_crtc_wm_config *config)
+{
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	mutex_lock(&dev_priv->wm.mutex);
+
+	spin_lock_irq(&crtc->wm.lock);
+	ilk_wm_cancel(crtc);
+	spin_unlock_irq(&crtc->wm.lock);
+
+	/* pending update (if any) got cancelled */
+	crtc->wm.pending = crtc->wm.active;
+
+	if (!memcmp(&crtc->wm.active, &config->intm, sizeof(config->intm)))
+		goto unlock;
+
+	crtc->wm.active = config->intm;
+
+	/* use the most up to date watermarks for other pipes */
+	ilk_refresh_pending_watermarks(dev);
+
+	/* switch over to the intermediate watermarks */
+	ilk_program_watermarks(dev);
+
+ unlock:
+	mutex_unlock(&dev_priv->wm.mutex);
+}
+
+static void ilk_program_wm_post(struct intel_crtc *crtc,
+				const struct intel_crtc_wm_config *config)
+{
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 vbl_count;
+
+	/*
+	 * FIXME sample this inside the atomic section to avoid
+	 * needlessly long periods w/ sub-par watermarks
+	 */
+	vbl_count = dev->driver->get_vblank_counter(dev, crtc->pipe);
+
+	mutex_lock(&dev_priv->wm.mutex);
+
+	/*
+	 * We can switch over to the target
+	 * watermarks after the next vblank.
+	 */
+	ilk_setup_pending_watermarks(crtc, &config->target, vbl_count);
+
+	mutex_unlock(&dev_priv->wm.mutex);
+}
+
 /* Set up chip specific power management-related functions */
 void intel_init_pm(struct drm_device *dev)
 {
@@ -6569,6 +6655,8 @@ void intel_init_pm(struct drm_device *dev)
 		     dev_priv->wm.spr_latency[0] && dev_priv->wm.cur_latency[0])) {
 			dev_priv->display.update_wm = ilk_update_wm;
 			dev_priv->display.update_sprite_wm = ilk_update_sprite_wm;
+			dev_priv->display.program_wm_pre = ilk_program_wm_pre;
+			dev_priv->display.program_wm_post = ilk_program_wm_post;
 		} else {
 			DRM_DEBUG_KMS("Failed to read display plane latency. "
 				      "Disable CxSR\n");
-- 
1.8.5.5

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