[PATCH] drm/virtio: fail init on display-info timeout

[Pengpeng Hou]

virtio_gpu_init() sends GET_DISPLAY_INFO when scanouts are present and
waits for display_info_pending to clear. If the response never arrives,
the wait result is ignored and probe still succeeds.

Return -ETIMEDOUT on display-info timeout. Because this happens after
virtio_device_ready(), reset the device and tear down modesetting before
using the existing vbuf and virtqueue cleanup path.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_kms.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index cfde9f573df6..31209bea97ae 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -262,11 +262,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 			virtio_gpu_cmd_get_edids(vgdev);
 		virtio_gpu_cmd_get_display_info(vgdev);
 		virtio_gpu_notify(vgdev);
-		wait_event_timeout(vgdev->resp_wq, !vgdev->display_info_pending,
-				   5 * HZ);
+		if (!wait_event_timeout(vgdev->resp_wq,
+					!vgdev->display_info_pending,
+					5 * HZ)) {
+			DRM_ERROR("timed out waiting for display info\n");
+			ret = -ETIMEDOUT;
+			goto err_ready;
+		}
 	}
 	return 0;
 
+err_ready:
+	virtio_reset_device(vgdev->vdev);
+	virtio_gpu_modeset_fini(vgdev);
 err_scanouts:
 	virtio_gpu_free_vbufs(vgdev);
 err_vbufs:
-- 
2.50.1 (Apple Git-155)