[PATCH v1] drm/virtio: Fix driver removal with disabled KMS

[Dmitry Osipenko <dmitry.osipenko@collabora.com>]

DRM atomic and modesetting aren't initialized if virtio-gpu driver built
with disabled KMS, leading to access of uninitialized data on driver
removal/unbinding and crashing kernel. Fix it by skipping shutting down
atomic core with unavailable KMS.

Fixes: 72122c69d717 ("drm/virtio: Add option to disable KMS support")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index f0fb784c0f6f..2aaa7cb08085 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -138,7 +138,10 @@ static void virtio_gpu_remove(struct virtio_device *vdev)
 
 	virtio_gpu_release_vqs(dev);
 	drm_dev_unplug(dev);
-	drm_atomic_helper_shutdown(dev);
+
+	if (drm_core_check_feature(dev, DRIVER_ATOMIC))
+		drm_atomic_helper_shutdown(dev);
+
 	virtio_gpu_deinit(dev);
 	drm_dev_put(dev);
 }
-- 
2.54.0