[PATCH 3/3] drm: Reject DRI1 hw lock ioctl functions for kms drivers

Daniel Vetter daniel.vetter at ffwll.ch
Tue Jun 23 02:37:08 PDT 2015

I've done some extensive history digging across libdrm, mesa and
xf86-video-{intel,nouveau,ati}. The only potential user of this with
kms drivers I could find was ttmtest, which once used drmGetLock
still. But that mistake was quickly fixed up. Even the intel xvmc
library (which otherwise was really good with using dri1 stuff in kms
mode) managed to never take the hw lock for dri2 (and hence kms).

Hence it should be save to unconditionally disallow this.

Cc: Peter Antoine <peter.antoine at intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
 drivers/gpu/drm/drm_lock.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index f861361a635e..4924d381b664 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -61,6 +61,9 @@ int drm_legacy_lock(struct drm_device *dev, void *data,
 	struct drm_master *master = file_priv->master;
 	int ret = 0;
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
 	if (lock->context == DRM_KERNEL_CONTEXT) {
@@ -153,6 +156,9 @@ int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_
 	struct drm_lock *lock = data;
 	struct drm_master *master = file_priv->master;
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
 	if (lock->context == DRM_KERNEL_CONTEXT) {
 		DRM_ERROR("Process %d using kernel context %d\n",
 			  task_pid_nr(current), lock->context);

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