[PATCH 5.15 114/136] nouveau: explicitly wait on the fence in nouveau_bo_move_m2mf

Greg Kroah-Hartman
2022-08-29T11:21:04Z

From: Karol Herbst <kherbst@redhat.com>

commit 6b04ce966a738ecdd9294c9593e48513c0dc90aa upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/nouveau/nouveau_bo.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 05076e530e7d..e29175e4b44c 100644
--- 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,
--
2.37.2