[PATCH 2/5] drm/i915: Add sys FBC toggle interface

[Alexandra Yates <alexandra.yates@linux.intel.com>]

This interface allows an immediate enabling of FBC feature. What allow us
to see immediately the FBC power management savings and will allow us to
expose this through sysfs interface for powertop to leverage its
functionality.

Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |  1 +
 drivers/gpu/drm/i915/i915_sysfs.c    | 77 ++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_display.c | 15 +++++--
 drivers/gpu/drm/i915/intel_drv.h     |  4 +-
 drivers/gpu/drm/i915/intel_fbc.c     | 29 +++++++++++---
 5 files changed, 115 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c96da4d..0f3a37f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -936,6 +936,7 @@ struct intel_fbc {
 	} work;
 
 	const char *no_fbc_reason;
+	bool sysfs_set;
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 208c6ec..50d45ef 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -107,6 +107,65 @@ show_media_rc6_ms(struct device *kdev, struct device_attribute *attr, char *buf)
 }
 
 static ssize_t
+show_fbc(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	struct drm_minor *dminor = dev_to_drm_minor(kdev);
+	struct drm_device *dev = dminor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	ssize_t ret;
+
+	mutex_lock(&dev_priv->fbc.lock);
+	ret = snprintf(buf, PAGE_SIZE, "%s\n", dev_priv->fbc.enabled ?
+			"enabled":"disabled");
+	mutex_unlock(&dev_priv->fbc.lock);
+	return ret;
+}
+
+static ssize_t
+toggle_fbc(struct device *kdev, struct device_attribute *attr,
+	const char *buf, size_t count)
+{
+	struct drm_minor *dminor = dev_to_drm_minor(kdev);
+	struct drm_device *dev = dminor->dev;
+	struct intel_connector *connector;
+	struct intel_encoder *encoder;
+	struct intel_crtc *crtc = NULL;
+	u32 val;
+	ssize_t ret;
+	bool sysfs_set = true;
+
+	ret = kstrtou32(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	for_each_intel_connector(dev, connector) {
+		if (!connector->base.encoder)
+			continue;
+		encoder = to_intel_encoder(connector->base.encoder);
+		crtc = to_intel_crtc(encoder->base.crtc);
+	}
+
+	if (!crtc)
+		return -ENODEV;
+	switch (val) {
+	case 0:
+		ret = intel_fbc_disable(crtc, sysfs_set);
+		if (ret)
+			return ret;
+		break;
+	case 1:
+		ret = intel_fbc_enable(crtc, sysfs_set);
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EINVAL;
+
+	}
+	return count;
+}
+
+static ssize_t
 show_psr(struct device *kdev, struct device_attribute *attr, char *buf)
 {
 	struct drm_minor *dminor = dev_to_drm_minor(kdev);
@@ -167,6 +226,7 @@ toggle_psr(struct device *kdev, struct device_attribute *attr,
 	return count;
 }
 
+static DEVICE_ATTR(fbc_enable, S_IRUGO | S_IWUSR, show_fbc, toggle_fbc);
 static DEVICE_ATTR(psr_enable, S_IRUGO | S_IWUSR, show_psr, toggle_psr);
 static DEVICE_ATTR(rc6_enable, S_IRUGO, show_rc6_mask, NULL);
 static DEVICE_ATTR(rc6_residency_ms, S_IRUGO, show_rc6_ms, NULL);
@@ -174,6 +234,16 @@ static DEVICE_ATTR(rc6p_residency_ms, S_IRUGO, show_rc6p_ms, NULL);
 static DEVICE_ATTR(rc6pp_residency_ms, S_IRUGO, show_rc6pp_ms, NULL);
 static DEVICE_ATTR(media_rc6_residency_ms, S_IRUGO, show_media_rc6_ms, NULL);
 
+static struct attribute *fbc_attrs[] = {
+	&dev_attr_fbc_enable.attr,
+	NULL
+};
+
+static struct attribute_group fbc_attr_group = {
+	.name = power_group_name,
+	.attrs = fbc_attrs
+};
+
 static struct attribute *psr_attrs[] = {
 	&dev_attr_psr_enable.attr,
 	NULL
@@ -668,6 +738,12 @@ void i915_setup_sysfs(struct drm_device *dev)
 	int ret;
 
 #ifdef CONFIG_PM
+	if (HAS_FBC(dev)) {
+		ret = sysfs_merge_group(&dev->primary->kdev->kobj,
+					&fbc_attr_group);
+		if (ret)
+			DRM_ERROR("FBC sysfs setup failed\n");
+	}
 	if (HAS_PSR(dev)) {
 		ret = sysfs_merge_group(&dev->primary->kdev->kobj,
 					&psr_attr_group);
@@ -730,6 +806,7 @@ void i915_teardown_sysfs(struct drm_device *dev)
 	device_remove_bin_file(dev->primary->kdev,  &dpf_attrs_1);
 	device_remove_bin_file(dev->primary->kdev,  &dpf_attrs);
 #ifdef CONFIG_PM
+	sysfs_unmerge_group(&dev->primary->kdev->kobj, &fbc_attr_group);
 	sysfs_unmerge_group(&dev->primary->kdev->kobj, &psr_attr_group);
 	sysfs_unmerge_group(&dev->primary->kdev->kobj, &rc6_attr_group);
 	sysfs_unmerge_group(&dev->primary->kdev->kobj, &rc6p_attr_group);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bf9e347..3d252b9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6254,7 +6254,8 @@ static void intel_crtc_disable_noatomic(struct drm_crtc *crtc)
 	for_each_encoder_on_crtc(crtc->dev, crtc, encoder)
 		encoder->base.crtc = NULL;
 
-	intel_fbc_disable(intel_crtc);
+	if (dev_priv->fbc.sysfs_set != true)
+		intel_fbc_disable(intel_crtc, dev_priv->fbc.sysfs_set);
 	intel_update_watermarks(crtc);
 	intel_disable_shared_dpll(intel_crtc);
 
@@ -13586,7 +13587,10 @@ static int intel_atomic_commit(struct drm_device *dev,
 			intel_crtc_disable_planes(crtc, old_crtc_state->plane_mask);
 			dev_priv->display.crtc_disable(crtc);
 			intel_crtc->active = false;
-			intel_fbc_disable(intel_crtc);
+
+			if (dev_priv->fbc.sysfs_set != true)
+				intel_fbc_disable(intel_crtc,
+						dev_priv->fbc.sysfs_set);
 			intel_disable_shared_dpll(intel_crtc);
 
 			/*
@@ -13632,8 +13636,11 @@ static int intel_atomic_commit(struct drm_device *dev,
 			intel_pre_plane_update(to_intel_crtc_state(old_crtc_state));
 
 		if (crtc->state->active &&
-		    drm_atomic_get_existing_plane_state(state, crtc->primary))
-			intel_fbc_enable(intel_crtc);
+		    drm_atomic_get_existing_plane_state(state, crtc->primary)) {
+			if (dev_priv->fbc.sysfs_set != true)
+				intel_fbc_enable(intel_crtc,
+						dev_priv->fbc.sysfs_set);
+		}
 
 		if (crtc->state->active &&
 		    (crtc->state->planes_changed || update_pipe))
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 199e8cc..93d09cc 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1373,8 +1373,8 @@ void intel_fbc_pre_update(struct intel_crtc *crtc);
 void intel_fbc_post_update(struct intel_crtc *crtc);
 void intel_fbc_init(struct drm_i915_private *dev_priv);
 void intel_fbc_init_pipe_state(struct drm_i915_private *dev_priv);
-void intel_fbc_enable(struct intel_crtc *crtc);
-void intel_fbc_disable(struct intel_crtc *crtc);
+int intel_fbc_enable(struct intel_crtc *crtc, bool sysfs_set);
+int intel_fbc_disable(struct intel_crtc *crtc, bool sysfs_set);
 void intel_fbc_global_disable(struct drm_i915_private *dev_priv);
 void intel_fbc_invalidate(struct drm_i915_private *dev_priv,
 			  unsigned int frontbuffer_bits,
diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index d5a7cfe..d6154e5 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1083,19 +1083,24 @@ out:
 /**
  * intel_fbc_enable: tries to enable FBC on the CRTC
  * @crtc: the CRTC
+ * @sysfs_set: Identifies if this featudre is set from sysfs.
  *
  * This function checks if the given CRTC was chosen for FBC, then enables it if
  * possible. Notice that it doesn't activate FBC. It is valid to call
  * intel_fbc_enable multiple times for the same pipe without an
  * intel_fbc_disable in the middle, as long as it is deactivated.
+ *
+ * Returns:
+ * 0 on success and -errno otherwise
  */
-void intel_fbc_enable(struct intel_crtc *crtc)
+int intel_fbc_enable(struct intel_crtc *crtc, bool sysfs_set)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
 	struct intel_fbc *fbc = &dev_priv->fbc;
+	int ret = 0;
 
 	if (!fbc_supported(dev_priv))
-		return;
+		return -EINVAL;
 
 	mutex_lock(&fbc->lock);
 
@@ -1105,11 +1110,14 @@ void intel_fbc_enable(struct intel_crtc *crtc)
 			WARN_ON(!crtc->config->enable_fbc);
 			WARN_ON(fbc->active);
 		}
+		ret = -EALREADY;
 		goto out;
 	}
 
-	if (!crtc->config->enable_fbc)
+	if (!crtc->config->enable_fbc) {
+		ret = -EINVAL;
 		goto out;
+	}
 
 	WARN_ON(fbc->active);
 	WARN_ON(fbc->crtc != NULL);
@@ -1117,6 +1125,7 @@ void intel_fbc_enable(struct intel_crtc *crtc)
 	intel_fbc_update_state_cache(crtc);
 	if (intel_fbc_alloc_cfb(crtc)) {
 		fbc->no_fbc_reason = "not enough stolen memory";
+		ret = -EINVAL;
 		goto out;
 	}
 
@@ -1125,8 +1134,11 @@ void intel_fbc_enable(struct intel_crtc *crtc)
 
 	fbc->enabled = true;
 	fbc->crtc = crtc;
+	if (sysfs_set)
+		dev_priv->fbc.sysfs_set = sysfs_set;
 out:
 	mutex_unlock(&fbc->lock);
+	return ret;
 }
 
 /**
@@ -1157,26 +1169,33 @@ static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
 /**
  * intel_fbc_disable - disable FBC if it's associated with crtc
  * @crtc: the CRTC
+ * @sysfs_set: Identifies if this featudre is set from sysfs.
  *
  * This function disables FBC if it's associated with the provided CRTC.
+ *
+ * Returns:
+ * 0 on success and -errno otherwise
  */
-void intel_fbc_disable(struct intel_crtc *crtc)
+int intel_fbc_disable(struct intel_crtc *crtc, bool sysfs_set)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
 	struct intel_fbc *fbc = &dev_priv->fbc;
 
 	if (!fbc_supported(dev_priv))
-		return;
+		return -EINVAL;
 
 	mutex_lock(&fbc->lock);
 	if (fbc->crtc == crtc) {
 		WARN_ON(!fbc->enabled);
 		WARN_ON(fbc->active);
 		__intel_fbc_disable(dev_priv);
+		if (sysfs_set)
+			dev_priv->fbc.sysfs_set = sysfs_set;
 	}
 	mutex_unlock(&fbc->lock);
 
 	cancel_work_sync(&fbc->work.work);
+	return 0;
 }
 
 /**
-- 
2.5.0

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