drm/i915: FBC doesn't need struct_mutex anymore

Everything is covered either by fbc.lock or mm.stolen_lock, and
intel_fbc.c is already responsible for grabbing the appropriate locks
when it needs them.
Reviewed-by: NChris wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1660,9 +1660,7 @@ static int i915_fbc_fc_get(void *data, u64 *val)
 	if (INTEL_INFO(dev)->gen < 7 || !HAS_FBC(dev))
 		return -ENODEV;
 
-	drm_modeset_lock_all(dev);
 	*val = dev_priv->fbc.false_color;
-	drm_modeset_unlock_all(dev);
 
 	return 0;
 }
@@ -1676,7 +1674,6 @@ static int i915_fbc_fc_set(void *data, u64 val)
 	if (INTEL_INFO(dev)->gen < 7 || !HAS_FBC(dev))
 		return -ENODEV;
 
-	drm_modeset_lock_all(dev);
 	mutex_lock(&dev_priv->fbc.lock);
 
 	reg = I915_READ(ILK_DPFC_CONTROL);
@@ -1687,7 +1684,6 @@ static int i915_fbc_fc_set(void *data, u64 val)
 		   (reg & ~FBC_CTL_FALSE_COLOR));
 
 	mutex_unlock(&dev_priv->fbc.lock);
-	drm_modeset_unlock_all(dev);
 	return 0;
 }
 

drivers/gpu/drm/i915/intel_display.c

@@ -4747,11 +4747,8 @@ static void intel_post_plane_update(struct intel_crtc *crtc)
 	if (crtc->atomic.update_wm_post)
 		intel_update_watermarks(&crtc->base);
 
-	if (atomic->update_fbc) {
-		mutex_lock(&dev->struct_mutex);
+	if (atomic->update_fbc)
 		intel_fbc_update(dev);
-		mutex_unlock(&dev->struct_mutex);
-	}
 
 	if (atomic->post_enable_primary)
 		intel_post_enable_primary(&crtc->base);
@@ -4783,11 +4780,8 @@ static void intel_pre_plane_update(struct intel_crtc *crtc)
 	if (atomic->wait_for_flips)
 		intel_crtc_wait_for_pending_flips(&crtc->base);
 
-	if (atomic->disable_fbc) {
-		mutex_lock(&dev->struct_mutex);
+	if (atomic->disable_fbc)
 		intel_fbc_disable_crtc(crtc);
-		mutex_unlock(&dev->struct_mutex);
-	}
 
 	if (crtc->atomic.disable_ips)
 		hsw_disable_ips(crtc);
@@ -11473,9 +11467,9 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 
 	i915_gem_track_fb(intel_fb_obj(work->old_fb), obj,
 			  to_intel_plane(primary)->frontbuffer_bit);
+	mutex_unlock(&dev->struct_mutex);
 
 	intel_fbc_disable(dev);
-	mutex_unlock(&dev->struct_mutex);
 	intel_frontbuffer_flip_prepare(dev,
 				       to_intel_plane(primary)->frontbuffer_bit);
 
@@ -15605,9 +15599,7 @@ void intel_modeset_cleanup(struct drm_device *dev)
 
 	intel_unregister_dsm_handler();
 
-	mutex_lock(&dev->struct_mutex);
 	intel_fbc_disable(dev);
-	mutex_unlock(&dev->struct_mutex);
 
 	/* flush any delayed tasks or pending work */
 	flush_scheduled_work();

drivers/gpu/drm/i915/intel_fbc.c

@@ -335,7 +335,6 @@ static void intel_fbc_work_fn(struct work_struct *__work)
 	struct drm_device *dev = work->crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	mutex_lock(&dev->struct_mutex);
 	mutex_lock(&dev_priv->fbc.lock);
 	if (work == dev_priv->fbc.fbc_work) {
 		/* Double check that we haven't switched fb without cancelling
@@ -352,7 +351,6 @@ static void intel_fbc_work_fn(struct work_struct *__work)
 		dev_priv->fbc.fbc_work = NULL;
 	}
 	mutex_unlock(&dev_priv->fbc.lock);
-	mutex_unlock(&dev->struct_mutex);
 
 	kfree(work);
 }