From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Mon, 5 Mar 2018 13:36:08 +0100
Subject: drm/i915: Handle changing enable_fbc parameter at runtime better.
Git-commit: 949f7c7d5fc4277e1ca91dbee32ceb469bbb1349
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

If i915.enable_fbc is cleared at runtime, but FBC was previously enabled
then we don't disable FBC until the next time the crtc is disabled.

Make sure that if the module param is changed, we disable FBC in
intel_fbc_post_update so we never have to worry about disabling.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180305123608.20665-1-maarten.lankhorst@linux.intel.com
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/intel_fbc.c |   62 ++++++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 26 deletions(-)

--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -960,6 +960,30 @@ unlock:
 	mutex_unlock(&fbc->lock);
 }
 
+/**
+ * __intel_fbc_disable - disable FBC
+ * @dev_priv: i915 device instance
+ *
+ * This is the low level function that actually disables FBC. Callers should
+ * grab the FBC lock.
+ */
+static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
+{
+	struct intel_fbc *fbc = &dev_priv->fbc;
+	struct intel_crtc *crtc = fbc->crtc;
+
+	WARN_ON(!mutex_is_locked(&fbc->lock));
+	WARN_ON(!fbc->enabled);
+	WARN_ON(fbc->active);
+
+	DRM_DEBUG_KMS("Disabling FBC on pipe %c\n", pipe_name(crtc->pipe));
+
+	__intel_fbc_cleanup_cfb(dev_priv);
+
+	fbc->enabled = false;
+	fbc->crtc = NULL;
+}
+
 static void __intel_fbc_post_update(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
@@ -971,6 +995,13 @@ static void __intel_fbc_post_update(stru
 	if (!fbc->enabled || fbc->crtc != crtc)
 		return;
 
+	if (!i915_modparams.enable_fbc) {
+		intel_fbc_deactivate(dev_priv, "disabled at runtime per module param");
+		__intel_fbc_disable(dev_priv);
+
+		return;
+	}
+
 	if (!intel_fbc_can_activate(crtc)) {
 		WARN_ON(fbc->active);
 		return;
@@ -1175,31 +1206,6 @@ out:
 }
 
 /**
- * __intel_fbc_disable - disable FBC
- * @dev_priv: i915 device instance
- *
- * This is the low level function that actually disables FBC. Callers should
- * grab the FBC lock.
- */
-static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
-{
-	struct intel_fbc *fbc = &dev_priv->fbc;
-	struct intel_crtc *crtc = fbc->crtc;
-
-	WARN_ON(!mutex_is_locked(&fbc->lock));
-	WARN_ON(!fbc->enabled);
-	WARN_ON(fbc->active);
-	WARN_ON(crtc->active);
-
-	DRM_DEBUG_KMS("Disabling FBC on pipe %c\n", pipe_name(crtc->pipe));
-
-	__intel_fbc_cleanup_cfb(dev_priv);
-
-	fbc->enabled = false;
-	fbc->crtc = NULL;
-}
-
-/**
  * intel_fbc_disable - disable FBC if it's associated with crtc
  * @crtc: the CRTC
  *
@@ -1213,6 +1219,8 @@ void intel_fbc_disable(struct intel_crtc
 	if (!fbc_supported(dev_priv))
 		return;
 
+	WARN_ON(crtc->active);
+
 	mutex_lock(&fbc->lock);
 	if (fbc->crtc == crtc)
 		__intel_fbc_disable(dev_priv);
@@ -1235,8 +1243,10 @@ void intel_fbc_global_disable(struct drm
 		return;
 
 	mutex_lock(&fbc->lock);
-	if (fbc->enabled)
+	if (fbc->enabled) {
+		WARN_ON(fbc->crtc->active);
 		__intel_fbc_disable(dev_priv);
+	}
 	mutex_unlock(&fbc->lock);
 
 	cancel_work_sync(&fbc->work.work);