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Commit 48f243c9 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: move submit fence wait out of struct_mutex 



Probably a symptom of needing finer grained locking, but if we wait on
the incoming fence-fd (which could come from a different context) while
holding struct_mutex, that blocks retire_worker so gpu fences cannot get
signalled.

This causes a problem if userspace manages to get more than a frame
ahead, leaving the atomic-commit worker blocked waiting on fences that
cannot be signaled because submit is blocked waiting for a fence
signalled from vblank (after the atomic commit which is blocked).

If we start having multiple fence ctxs for the gpu, submit_fence_sync()
would probably need to move outside of struct_mutex as well.

Signed-off-by: default avatarRob Clark <robdclark@gmail.com>
parent cc692726

drivers/gpu/drm/msm/msm_gem_submit.c

+18 −21
Original line number Diff line number Diff line
@@ -404,6 +404,24 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, 
	if (MSM_PIPE_FLAGS(args->flags) & ~MSM_SUBMIT_FLAGS)

		return -EINVAL;



	if (args->flags & MSM_SUBMIT_FENCE_FD_IN) {

		in_fence = sync_file_get_fence(args->fence_fd);



		if (!in_fence)

			return -EINVAL;



		/* TODO if we get an array-fence due to userspace merging multiple

		 * fences, we need a way to determine if all the backing fences

		 * are from our own context..

		 */



		if (in_fence->context != gpu->fctx->context) {

			ret = dma_fence_wait(in_fence, true);

			if (ret)

				return ret;

		}

	}



	ret = mutex_lock_interruptible(&dev->struct_mutex);

	if (ret)

		return ret;
@@ -431,27 +449,6 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, 
	if (ret)

		goto out;



	if (args->flags & MSM_SUBMIT_FENCE_FD_IN) {

		in_fence = sync_file_get_fence(args->fence_fd);



		if (!in_fence) {

			ret = -EINVAL;

			goto out;

		}



		/* TODO if we get an array-fence due to userspace merging multiple

		 * fences, we need a way to determine if all the backing fences

		 * are from our own context..

		 */



		if (in_fence->context != gpu->fctx->context) {

			ret = dma_fence_wait(in_fence, true);

			if (ret)

				goto out;

		}



	}



	if (!(args->fence & MSM_SUBMIT_NO_IMPLICIT)) {

		ret = submit_fence_sync(submit);

		if (ret)