[PATCH] drm: Require universal_planes for atomic

[Daniel Vetter]

Atomic doesn't really work without universal planes anyway. But make
sure that evil userspace doesn't pull the kernel over the table
because we didn't consider a cornercase that just doesn't make sense,
just for safety.

Only requirement imposed on userspace by this is that it asks for
universal planes before it asks for atomic.

Cc: Rob Clark <robdclark at gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 5cb405812245..255bf5d45037 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -350,6 +350,8 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
 		/* for now, hide behind experimental drm.atomic moduleparam */
 		if (!drm_atomic)
 			return -EINVAL;
+		if (!file_priv->universal_planes)
+			return -EINVAL;
 		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
 			return -EINVAL;
 		if (req->value > 1)
-- 
2.1.3