drm/exynos: fix pending update handling

Exynos DRM devices update their registers at vblank time. Exynos-DRM uses
custom mechanism to wait for vblank. This mechanism is error prone -
variables are not updated atomically. As a result in certain circumstances
user space can try to free buffers which are still in use by hardware,
in such cases IOMMU can throw OOPS.
The patch instead of fixing the mechanism replaces it with drm core helper.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

1 files changed, 1 insertions, 43 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
index 486943e70f70..def78c8c1780 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -45,37 +45,11 @@ struct exynos_atomic_commit {
 	u32			crtcs;
 };
 
-static void exynos_atomic_wait_for_commit(struct drm_atomic_state *state)
-{
-	struct drm_crtc_state *crtc_state;
-	struct drm_crtc *crtc;
-	int i, ret;
-
-	for_each_crtc_in_state(state, crtc, crtc_state, i) {
-		struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
-
-		if (!crtc->state->enable)
-			continue;
-
-		ret = drm_crtc_vblank_get(crtc);
-		if (ret)
-			continue;
-
-		exynos_drm_crtc_wait_pending_update(exynos_crtc);
-		drm_crtc_vblank_put(crtc);
-	}
-}
-
 static void exynos_atomic_commit_complete(struct exynos_atomic_commit *commit)
 {
 	struct drm_device *dev = commit->dev;
 	struct exynos_drm_private *priv = dev->dev_private;
 	struct drm_atomic_state *state = commit->state;
-	struct drm_plane *plane;
-	struct drm_crtc *crtc;
-	struct drm_plane_state *plane_state;
-	struct drm_crtc_state *crtc_state;
-	int i;
 
 	drm_atomic_helper_commit_modeset_disables(dev, state);
 
@@ -89,25 +63,9 @@ static void exynos_atomic_commit_complete(struct exynos_atomic_commit *commit)
 	 * have the relevant clocks enabled to perform the update.
 	 */
 
-	for_each_crtc_in_state(state, crtc, crtc_state, i) {
-		struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
-
-		atomic_set(&exynos_crtc->pending_update, 0);
-	}
-
-	for_each_plane_in_state(state, plane, plane_state, i) {
-		struct exynos_drm_crtc *exynos_crtc =
-						to_exynos_crtc(plane->crtc);
-
-		if (!plane->crtc)
-			continue;
-
-		atomic_inc(&exynos_crtc->pending_update);
-	}
-
 	drm_atomic_helper_commit_planes(dev, state, 0);
 
-	exynos_atomic_wait_for_commit(state);
+	drm_atomic_helper_wait_for_vblanks(dev, state);
 
 	drm_atomic_helper_cleanup_planes(dev, state);