drm/i915: Drop struct_mutex around frontbuffer flushes

Since the frontbuffer has self-contained locking, it does not require us
to hold the BKL struct_mutex as we send invalidate and flush messages.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170215105919.7347-3-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/intel_fbdev.c

@@ -45,6 +45,14 @@
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
 
+static void intel_fbdev_invalidate(struct intel_fbdev *ifbdev)
+{
+	struct drm_i915_gem_object *obj = ifbdev->fb->obj;
+	unsigned int origin = ifbdev->vma->fence ? ORIGIN_GTT : ORIGIN_CPU;
+
+	intel_fb_obj_invalidate(obj, origin);
+}
+
 static int intel_fbdev_set_par(struct fb_info *info)
 {
 	struct drm_fb_helper *fb_helper = info->par;
@@ -53,12 +61,8 @@ static int intel_fbdev_set_par(struct fb_info *info)
 	int ret;
 
 	ret = drm_fb_helper_set_par(info);
-
-	if (ret == 0) {
-		mutex_lock(&fb_helper->dev->struct_mutex);
-		intel_fb_obj_invalidate(ifbdev->fb->obj, ORIGIN_GTT);
-		mutex_unlock(&fb_helper->dev->struct_mutex);
-	}
+	if (ret == 0)
+		intel_fbdev_invalidate(ifbdev);
 
 	return ret;
 }
@@ -71,12 +75,8 @@ static int intel_fbdev_blank(int blank, struct fb_info *info)
 	int ret;
 
 	ret = drm_fb_helper_blank(blank, info);
-
-	if (ret == 0) {
-		mutex_lock(&fb_helper->dev->struct_mutex);
-		intel_fb_obj_invalidate(ifbdev->fb->obj, ORIGIN_GTT);
-		mutex_unlock(&fb_helper->dev->struct_mutex);
-	}
+	if (ret == 0)
+		intel_fbdev_invalidate(ifbdev);
 
 	return ret;
 }
@@ -87,15 +87,11 @@ static int intel_fbdev_pan_display(struct fb_var_screeninfo *var,
 	struct drm_fb_helper *fb_helper = info->par;
 	struct intel_fbdev *ifbdev =
 		container_of(fb_helper, struct intel_fbdev, helper);
-
 	int ret;
-	ret = drm_fb_helper_pan_display(var, info);
 
-	if (ret == 0) {
-		mutex_lock(&fb_helper->dev->struct_mutex);
-		intel_fb_obj_invalidate(ifbdev->fb->obj, ORIGIN_GTT);
-		mutex_unlock(&fb_helper->dev->struct_mutex);
-	}
+	ret = drm_fb_helper_pan_display(var, info);
+	if (ret == 0)
+		intel_fbdev_invalidate(ifbdev);
 
 	return ret;
 }
@@ -838,11 +834,6 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
 	if (!ifbdev->fb)
 		return;
 
-	if (drm_fb_helper_restore_fbdev_mode_unlocked(&ifbdev->helper)) {
-		DRM_DEBUG("failed to restore crtc mode\n");
-	} else {
-		mutex_lock(&dev->struct_mutex);
-		intel_fb_obj_invalidate(ifbdev->fb->obj, ORIGIN_GTT);
-		mutex_unlock(&dev->struct_mutex);
-	}
+	if (drm_fb_helper_restore_fbdev_mode_unlocked(&ifbdev->helper) == 0)
+		intel_fbdev_invalidate(ifbdev);
 }