[PATCH v3 23/23] drm/msm: Don't implicit-sync if only a single ring

Rob Clark
2020-10-19T20:46:32Z

If there is only a single ring (no-preemption), everything is FIFO order
and there is no need to implicit-sync.

Mesa should probably just always use MSM_SUBMIT_NO_IMPLICIT, as behavior
is undefined when fences are not used to synchronize buffer usage across
contexts (which is the only case where multiple different priority rings
could come into play).

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/gpu/drm/msm/msm_gem_submit.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index d784e97f233f..96832debc3b6 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -277,7 +277,7 @@ static int submit_lock_objects(struct msm_gem_submit *submit)
return ret;
}

-static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
+static int submit_fence_sync(struct msm_gem_submit *submit, bool implicit_sync)
{
int i, ret = 0;

@@ -297,7 +297,7 @@ static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
return ret;
}

- if (no_implicit)
+ if (!implicit_sync)
continue;

ret = msm_gem_sync_object(&msm_obj->base, submit->ring->fctx,
@@ -768,7 +768,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
if (ret)
goto out;

- ret = submit_fence_sync(submit, !!(args->flags & MSM_SUBMIT_NO_IMPLICIT));
+ ret = submit_fence_sync(submit, (gpu->nr_rings > 1) &&
+ !(args->flags & MSM_SUBMIT_NO_IMPLICIT));
if (ret)
goto out;

--
2.26.2