drm/vmwgfx: Kill some lockdep warnings

Some global KMS state that is elsewhere protected by the mode_config
mutex here needs to be protected with a local mutex. Remove corresponding
lockdep checks and introduce a new driver-private global_kms_state_mutex,
and make sure its locking order is *after* the crtc locks in order to
avoid having to release those when the new mutex is taken.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Cc: <stable@vger.kernel.org> # 4.6

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
index 0ea22fd112c9..b74eae2b8594 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -285,14 +285,17 @@ static int vmw_sou_crtc_set_config(struct drm_mode_set *set)
         }
 
         /* Only one active implicit frame-buffer at a time. */
+        mutex_lock(&dev_priv->global_kms_state_mutex);
         if (sou->base.is_implicit &&
             dev_priv->implicit_fb && vfb &&
             !(dev_priv->num_implicit == 1 &&
               sou->base.active_implicit) &&
             dev_priv->implicit_fb != vfb) {
+                mutex_unlock(&dev_priv->global_kms_state_mutex);
                 DRM_ERROR("Multiple implicit framebuffers not supported.\n");
                 return -EINVAL;
         }
+        mutex_unlock(&dev_priv->global_kms_state_mutex);
 
         /* since they always map one to one these are safe */
         connector = &sou->base.connector;