gpu: nvgpu: fix semaphore wakeup logic

Currently, when we receive a semaphore wakeup interrupt,
we call the channel_update callback, which schedules
deferred job clean-up.

For deterministic channels, we don't allow semaphore-backed
syncs anyways. That means for these channels, if we get a
semaphore wakeup interrupt, it must be for a userspace-managed
semaphore. In this case, there is no need to call into the
channel_update callback. So for deterministic channels, we
skip this.

Bug 1795076

Change-Id: I4cdfecd53144078c5cd4be8a41c5c3b7d74c338e
Signed-off-by: Sachit Kadle <skadle@nvidia.com>
Reviewed-on: http://git-master/r/1225620
(cherry picked from commit 64a6db0080c3b198ddc2029544f52eb590dc08ff)
Reviewed-on: http://git-master/r/1225615
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 7481e747..6c4b949a 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -3341,7 +3341,17 @@ void gk20a_channel_semaphore_wakeup(struct gk20a *g, bool post_events)
                                             NVGPU_IOCTL_CHANNEL_EVENT_ID_BLOCKING_SYNC);
                                 }
                         }
-                        gk20a_channel_update(c, 0);
+                        /*
+                         * Only non-deterministic channels get the
+                         * channel_update callback. We don't allow
+                         * semaphore-backed syncs for these channels anyways,
+                         * since they have a dependency on the sync framework.
+                         * If deterministic channels are receiving a semaphore
+                         * wakeup, it must be for a user-space managed
+                         * semaphore.
+                         */
+                        if (!c->deterministic)
+                                gk20a_channel_update(c, 0);
                         gk20a_channel_put(c);
                 }
         }