Revert "drm/i915: Enable RC6 immediately"

This reverts commit b12e0ee2 ("drm/i915: Enable RC6 immediately"),
as it was never meant to be sent anywhere other than the bug report for
experimentation.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1469132179-4052-1-git-send-email-chris@chris-wilson.co.ukAcked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -1630,6 +1630,7 @@ static int i915_drm_resume(struct drm_device *dev)
 
 	intel_opregion_notify_adapter(dev_priv, PCI_D0);
 
+	intel_autoenable_gt_powersave(dev_priv);
 	drm_kms_helper_poll_enable(dev);
 
 	enable_rpm_wakeref_asserts(dev_priv);
@@ -1811,8 +1812,7 @@ int i915_reset(struct drm_i915_private *dev_priv)
 	 * previous concerns that it doesn't respond well to some forms
 	 * of re-init after reset.
 	 */
-	if (INTEL_GEN(dev_priv) > 5)
-		intel_enable_gt_powersave(dev_priv);
+	intel_autoenable_gt_powersave(dev_priv);
 
 	return 0;
 
@@ -2440,7 +2440,6 @@ static int intel_runtime_resume(struct device *device)
 	i915_gem_init_swizzling(dev);
 
 	intel_runtime_pm_enable_interrupts(dev_priv);
-	intel_enable_gt_powersave(dev_priv);
 
 	/*
 	 * On VLV/CHV display interrupts are part of the display

drivers/gpu/drm/i915/i915_drv.h

@@ -1192,6 +1192,7 @@ struct intel_gen6_power_mgmt {
 	bool client_boost;
 
 	bool enabled;
+	struct delayed_work autoenable_work;
 	unsigned boosts;
 
 	/* manual wa residency calculations */

drivers/gpu/drm/i915/i915_gem.c

@@ -4355,6 +4355,8 @@ i915_gem_suspend(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	int ret = 0;
 
+	intel_suspend_gt_powersave(dev_priv);
+
 	mutex_lock(&dev->struct_mutex);
 
 	/* We have to flush all the executing contexts to main memory so

drivers/gpu/drm/i915/i915_gem_request.c

@@ -405,6 +405,7 @@ static void i915_gem_mark_busy(const struct intel_engine_cs *engine)
 	intel_runtime_pm_get_noresume(dev_priv);
 	dev_priv->gt.awake = true;
 
+	intel_enable_gt_powersave(dev_priv);
 	i915_update_gfx_val(dev_priv);
 	if (INTEL_GEN(dev_priv) >= 6)
 		gen6_rps_busy(dev_priv);

drivers/gpu/drm/i915/intel_display.c

@@ -15502,7 +15502,6 @@ void intel_modeset_init_hw(struct drm_device *dev)
 	dev_priv->atomic_cdclk_freq = dev_priv->cdclk_freq;
 
 	intel_init_clock_gating(dev);
-	intel_enable_gt_powersave(dev_priv);
 }
 
 /*

drivers/gpu/drm/i915/intel_drv.h

@@ -1691,9 +1691,12 @@ void intel_pm_setup(struct drm_device *dev);
 void intel_gpu_ips_init(struct drm_i915_private *dev_priv);
 void intel_gpu_ips_teardown(void);
 void intel_init_gt_powersave(struct drm_i915_private *dev_priv);
+void intel_cleanup_gt_powersave(struct drm_i915_private *dev_priv);
+void intel_sanitize_gt_powersave(struct drm_i915_private *dev_priv);
 void intel_enable_gt_powersave(struct drm_i915_private *dev_priv);
+void intel_autoenable_gt_powersave(struct drm_i915_private *dev_priv);
 void intel_disable_gt_powersave(struct drm_i915_private *dev_priv);
-void intel_cleanup_gt_powersave(struct drm_i915_private *dev_priv);
+void intel_suspend_gt_powersave(struct drm_i915_private *dev_priv);
 void gen6_rps_busy(struct drm_i915_private *dev_priv);
 void gen6_rps_reset_ei(struct drm_i915_private *dev_priv);
 void gen6_rps_idle(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/intel_pm.c

@@ -6526,6 +6526,8 @@ void intel_init_gt_powersave(struct drm_i915_private *dev_priv)
 	dev_priv->rps.boost_freq = dev_priv->rps.max_freq;
 
 	mutex_unlock(&dev_priv->rps.hw_lock);
+
+	intel_autoenable_gt_powersave(dev_priv);
 }
 
 void intel_cleanup_gt_powersave(struct drm_i915_private *dev_priv)
@@ -6539,10 +6541,31 @@ void intel_cleanup_gt_powersave(struct drm_i915_private *dev_priv)
 		intel_runtime_pm_put(dev_priv);
 }
 
+/**
+ * intel_suspend_gt_powersave - suspend PM work and helper threads
+ * @dev_priv: i915 device
+ *
+ * We don't want to disable RC6 or other features here, we just want
+ * to make sure any work we've queued has finished and won't bother
+ * us while we're suspended.
+ */
+void intel_suspend_gt_powersave(struct drm_i915_private *dev_priv)
+{
+	if (INTEL_GEN(dev_priv) < 6)
+		return;
+
+	if (cancel_delayed_work_sync(&dev_priv->rps.autoenable_work))
+		intel_runtime_pm_put(dev_priv);
+
+	/* gen6_rps_idle() will be called later to disable interrupts */
+}
+
 void intel_sanitize_gt_powersave(struct drm_i915_private *dev_priv)
 {
 	dev_priv->rps.enabled = true; /* force disabling */
 	intel_disable_gt_powersave(dev_priv);
+
+	gen6_reset_rps_interrupts(dev_priv);
 }
 
 void intel_disable_gt_powersave(struct drm_i915_private *dev_priv)
@@ -6567,12 +6590,13 @@ void intel_disable_gt_powersave(struct drm_i915_private *dev_priv)
 
 	dev_priv->rps.enabled = false;
 	mutex_unlock(&dev_priv->rps.hw_lock);
-
-	gen6_reset_rps_interrupts(dev_priv);
 }
 
 void intel_enable_gt_powersave(struct drm_i915_private *dev_priv)
 {
+	/* We shouldn't be disabling as we submit, so this should be less
+	 * racy than it appears!
+	 */
 	if (READ_ONCE(dev_priv->rps.enabled))
 		return;
 
@@ -6608,9 +6632,75 @@ void intel_enable_gt_powersave(struct drm_i915_private *dev_priv)
 	WARN_ON(dev_priv->rps.efficient_freq < dev_priv->rps.min_freq);
 	WARN_ON(dev_priv->rps.efficient_freq > dev_priv->rps.max_freq);
 
+	dev_priv->rps.enabled = true;
 	mutex_unlock(&dev_priv->rps.hw_lock);
 }
 
+static void __intel_autoenable_gt_powersave(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, typeof(*dev_priv), rps.autoenable_work.work);
+	struct intel_engine_cs *rcs;
+	struct drm_i915_gem_request *req;
+
+	if (READ_ONCE(dev_priv->rps.enabled))
+		goto out;
+
+	rcs = &dev_priv->engine[RCS];
+	if (rcs->last_context)
+		goto out;
+
+	if (!rcs->init_context)
+		goto out;
+
+	mutex_lock(&dev_priv->drm.struct_mutex);
+
+	req = i915_gem_request_alloc(rcs, dev_priv->kernel_context);
+	if (IS_ERR(req))
+		goto unlock;
+
+	if (!i915.enable_execlists && i915_switch_context(req) == 0)
+		rcs->init_context(req);
+
+	/* Mark the device busy, calling intel_enable_gt_powersave() */
+	i915_add_request_no_flush(req);
+
+unlock:
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+out:
+	intel_runtime_pm_put(dev_priv);
+}
+
+void intel_autoenable_gt_powersave(struct drm_i915_private *dev_priv)
+{
+	if (READ_ONCE(dev_priv->rps.enabled))
+		return;
+
+	if (IS_IRONLAKE_M(dev_priv)) {
+		ironlake_enable_drps(dev_priv);
+		mutex_lock(&dev_priv->drm.struct_mutex);
+		intel_init_emon(dev_priv);
+		mutex_unlock(&dev_priv->drm.struct_mutex);
+	} else if (INTEL_INFO(dev_priv)->gen >= 6) {
+		/*
+		 * PCU communication is slow and this doesn't need to be
+		 * done at any specific time, so do this out of our fast path
+		 * to make resume and init faster.
+		 *
+		 * We depend on the HW RC6 power context save/restore
+		 * mechanism when entering D3 through runtime PM suspend. So
+		 * disable RPM until RPS/RC6 is properly setup. We can only
+		 * get here via the driver load/system resume/runtime resume
+		 * paths, so the _noresume version is enough (and in case of
+		 * runtime resume it's necessary).
+		 */
+		if (queue_delayed_work(dev_priv->wq,
+				       &dev_priv->rps.autoenable_work,
+				       round_jiffies_up_relative(HZ)))
+			intel_runtime_pm_get_noresume(dev_priv);
+	}
+}
+
 static void ibx_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
@@ -7716,6 +7806,8 @@ void intel_pm_setup(struct drm_device *dev)
 	mutex_init(&dev_priv->rps.hw_lock);
 	spin_lock_init(&dev_priv->rps.client_lock);
 
+	INIT_DELAYED_WORK(&dev_priv->rps.autoenable_work,
+			  __intel_autoenable_gt_powersave);
 	INIT_LIST_HEAD(&dev_priv->rps.clients);
 
 	dev_priv->pm.suspended = false;

drivers/gpu/drm/i915/intel_uncore.c

@@ -435,7 +435,7 @@ void intel_uncore_sanitize(struct drm_i915_private *dev_priv)
 	i915.enable_rc6 = sanitize_rc6_option(dev_priv, i915.enable_rc6);
 
 	/* BIOS often leaves RC6 enabled, but disable it for hw init */
-	intel_disable_gt_powersave(dev_priv);
+	intel_sanitize_gt_powersave(dev_priv);
 }
 
 static void __intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,