drm/nouveau: wait on fence after bo move if validating for another channel

Not an ideal solution, but it'll do for the moment for correctness.  We
need to come up with a nicer way to manage inter-channel sync, the hw
is unfortunately a little lacking in this area.

Should fix some resume corruption, as well as corruption that may be seen
while under memory pressure.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index e342a418d434..db0ed4c13f98 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -469,6 +469,8 @@ nouveau_bo_move_accel_cleanup(struct nouveau_channel *chan,
 
         ret = ttm_bo_move_accel_cleanup(&nvbo->bo, fence, NULL,
                                         evict, no_wait, new_mem);
+        if (nvbo->channel && nvbo->channel != chan)
+                ret = nouveau_fence_wait(fence, NULL, false, false);
         nouveau_fence_unref((void *)&fence);
         return ret;
 }