Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide

[cascardo/linux.git] / drivers / gpu / drm / drm_fb_helper.c

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 1ddc174..d5d8cea 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -273,15 +273,7 @@ int drm_fb_helper_debug_leave(struct fb_info *info)
 }
 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
 
-/**
- * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
- * @fb_helper: fbcon to restore
- *
- * This should be called from driver's drm ->lastclose callback
- * when implementing an fbcon on top of kms using this helper. This ensures that
- * the user isn't greeted with a black screen when e.g. X dies.
- */
-bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
+static bool restore_fbdev_mode(struct drm_fb_helper *fb_helper)
 {
        struct drm_device *dev = fb_helper->dev;
        struct drm_plane *plane;
@@ -311,7 +303,40 @@ bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
        }
        return error;
 }
-EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);
+/**
+ * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
+ * @fb_helper: fbcon to restore
+ *
+ * This should be called from driver's drm ->lastclose callback
+ * when implementing an fbcon on top of kms using this helper. This ensures that
+ * the user isn't greeted with a black screen when e.g. X dies.
+ *
+ * Use this variant if you need to bypass locking (panic), or already
+ * hold all modeset locks.  Otherwise use drm_fb_helper_restore_fbdev_mode_unlocked()
+ */
+static bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
+{
+       return restore_fbdev_mode(fb_helper);
+}
+
+/**
+ * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
+ * @fb_helper: fbcon to restore
+ *
+ * This should be called from driver's drm ->lastclose callback
+ * when implementing an fbcon on top of kms using this helper. This ensures that
+ * the user isn't greeted with a black screen when e.g. X dies.
+ */
+bool drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+{
+       struct drm_device *dev = fb_helper->dev;
+       bool ret;
+       drm_modeset_lock_all(dev);
+       ret = restore_fbdev_mode(fb_helper);
+       drm_modeset_unlock_all(dev);
+       return ret;
+}
+EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
 
 /*
  * restore fbcon display for all kms driver's using this helper, used for sysrq
@@ -331,6 +356,10 @@ static bool drm_fb_helper_force_kernel_mode(void)
                if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
                        continue;
 
+               /* NOTE: we use lockless flag below to avoid grabbing other
+                * modeset locks.  So just trylock the underlying mutex
+                * directly:
+                */
                if (!mutex_trylock(&dev->mode_config.mutex)) {
                        error = true;
                        continue;
@@ -820,7 +849,6 @@ EXPORT_SYMBOL(drm_fb_helper_check_var);
 int drm_fb_helper_set_par(struct fb_info *info)
 {
        struct drm_fb_helper *fb_helper = info->par;
-       struct drm_device *dev = fb_helper->dev;
        struct fb_var_screeninfo *var = &info->var;
 
        if (var->pixclock != 0) {
@@ -828,9 +856,7 @@ int drm_fb_helper_set_par(struct fb_info *info)
                return -EINVAL;
        }
 
-       drm_modeset_lock_all(dev);
-       drm_fb_helper_restore_fbdev_mode(fb_helper);
-       drm_modeset_unlock_all(dev);
+       drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
 
        if (fb_helper->delayed_hotplug) {
                fb_helper->delayed_hotplug = false;