nouveau: explicitly wait on the fence in nouveau_bo_move_m2mf

It is a bit unlcear to us why that's helping, but it does and unbreaks
suspend/resume on a lot of GPUs without any known drawbacks.

Cc: stable@vger.kernel.org # v5.15+
Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/156
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220819200928.401416-1-kherbst@redhat.com

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 05076e5..e29175e 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -820,6 +820,15 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int evict,
                if (ret == 0) {
                        ret = nouveau_fence_new(chan, false, &fence);
                        if (ret == 0) {
+                               /* TODO: figure out a better solution here
+                                *
+                                * wait on the fence here explicitly as going through
+                                * ttm_bo_move_accel_cleanup somehow doesn't seem to do it.
+                                *
+                                * Without this the operation can timeout and we'll fallback to a
+                                * software copy, which might take several minutes to finish.
+                                */
+                               nouveau_fence_wait(fence, false, false);
                                ret = ttm_bo_move_accel_cleanup(bo,
                                                                &fence->base,
                                                                evict, false,