drm: review locking for drm_fb_helper_restore_fbdev_mode
... it's required. Fix up exynos and the cma helper, and add a
corresponding WARN_ON to drm_fb_helper_restore_fbdev_mode.
Note that tegra calls the fbdev cma helper restore function also from
it's driver-load callback. Which is a bit against current practice,
since usually the call is only from ->lastclose, and initial setup is
done by drm_fb_helper_initial_config.
Also add the relevant drm DocBook entry.
v2: Add promised WARN to restore_fbdev_mode.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 9c797f6..f170773 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -68,9 +68,23 @@
mutex_unlock(&dev->mode_config.mutex);
}
-
EXPORT_SYMBOL(drm_modeset_unlock_all);
+/**
+ * drm_warn_on_modeset_not_all_locked - check that all modeset locks are locked
+ * @dev: device
+ */
+void drm_warn_on_modeset_not_all_locked(struct drm_device *dev)
+{
+ struct drm_crtc *crtc;
+
+ list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+ WARN_ON(!mutex_is_locked(&crtc->mutex));
+
+ WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+}
+EXPORT_SYMBOL(drm_warn_on_modeset_not_all_locked);
+
/* Avoid boilerplate. I'm tired of typing. */
#define DRM_ENUM_NAME_FN(fnname, list) \
char *fnname(int val) \