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Commit 8f676c4c authored by Christian König's avatar Christian König Committed by Dave Airlie
Browse files

drm/radeon: fix a bug with the ring syncing code 



Rings need to lock in order, otherwise
the ring subsystem can deadlock.

v2: fix error handling and number of locked doublewords.
v3: stop creating unneeded semaphores.

Signed-off-by: default avatarChristian König <deathsimple@vodafone.de>
Reviewed-by: default avatarJerome Glisse <jglisse@redhat.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent bfb9a077

drivers/gpu/drm/radeon/radeon.h

+4 −0
Original line number Diff line number Diff line
@@ -460,6 +460,10 @@ void radeon_semaphore_emit_signal(struct radeon_device *rdev, int ring, 
				  struct radeon_semaphore *semaphore);

void radeon_semaphore_emit_wait(struct radeon_device *rdev, int ring,

				struct radeon_semaphore *semaphore);

int radeon_semaphore_sync_rings(struct radeon_device *rdev,

				struct radeon_semaphore *semaphore,

				bool sync_to[RADEON_NUM_RINGS],

				int dst_ring);

void radeon_semaphore_free(struct radeon_device *rdev,

			   struct radeon_semaphore *semaphore);

drivers/gpu/drm/radeon/radeon_cs.c

+12 −23
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ static int radeon_cs_get_ring(struct radeon_cs_parser *p, u32 ring, s32 priority 
static int radeon_cs_sync_rings(struct radeon_cs_parser *p)

{

	bool sync_to_ring[RADEON_NUM_RINGS] = { };

	bool need_sync = false;

	int i, r;



	for (i = 0; i < p->nrelocs; i++) {
@@ -126,36 +127,24 @@ static int radeon_cs_sync_rings(struct radeon_cs_parser *p) 


		if (!(p->relocs[i].flags & RADEON_RELOC_DONT_SYNC)) {

			struct radeon_fence *fence = p->relocs[i].robj->tbo.sync_obj;

			if (!radeon_fence_signaled(fence)) {

			if (fence->ring != p->ring && !radeon_fence_signaled(fence)) {

				sync_to_ring[fence->ring] = true;

				need_sync = true;

			}

		}

	}



	for (i = 0; i < RADEON_NUM_RINGS; ++i) {

		/* no need to sync to our own or unused rings */

		if (i == p->ring || !sync_to_ring[i] || !p->rdev->ring[i].ready)

			continue;

	if (!need_sync) {

		return 0;

	}



		if (!p->ib->fence->semaphore) {

	r = radeon_semaphore_create(p->rdev, &p->ib->fence->semaphore);

			if (r)

	if (r) {

		return r;

	}



		r = radeon_ring_lock(p->rdev, &p->rdev->ring[i], 3);

		if (r)

			return r;

		radeon_semaphore_emit_signal(p->rdev, i, p->ib->fence->semaphore);

		radeon_ring_unlock_commit(p->rdev, &p->rdev->ring[i]);



		r = radeon_ring_lock(p->rdev, &p->rdev->ring[p->ring], 3);

		if (r)

			return r;

		radeon_semaphore_emit_wait(p->rdev, p->ring, p->ib->fence->semaphore);

		radeon_ring_unlock_commit(p->rdev, &p->rdev->ring[p->ring]);

	}

	return 0;

	return radeon_semaphore_sync_rings(p->rdev, p->ib->fence->semaphore,

					   sync_to_ring, p->ring);

}



int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)

drivers/gpu/drm/radeon/radeon_semaphore.c

+56 −0
Original line number Diff line number Diff line
@@ -149,6 +149,62 @@ void radeon_semaphore_emit_wait(struct radeon_device *rdev, int ring, 
	radeon_semaphore_ring_emit(rdev, ring, &rdev->ring[ring], semaphore, true);

}



int radeon_semaphore_sync_rings(struct radeon_device *rdev,

				struct radeon_semaphore *semaphore,

				bool sync_to[RADEON_NUM_RINGS],

				int dst_ring)

{

	int i, r;



	for (i = 0; i < RADEON_NUM_RINGS; ++i) {

		unsigned num_ops = i == dst_ring ? RADEON_NUM_RINGS : 1;



		/* don't lock unused rings */

		if (!sync_to[i] && i != dst_ring)

			continue;



		/* prevent GPU deadlocks */

		if (!rdev->ring[i].ready) {

			dev_err(rdev->dev, "Trying to sync to a disabled ring!");

			r = -EINVAL;

			goto error;

		}



                r = radeon_ring_lock(rdev, &rdev->ring[i], num_ops * 8);

                if (r)

			goto error;

	}



	for (i = 0; i < RADEON_NUM_RINGS; ++i) {

		/* no need to sync to our own or unused rings */

		if (!sync_to[i] || i == dst_ring)

                        continue;



		radeon_semaphore_emit_signal(rdev, i, semaphore);

		radeon_semaphore_emit_wait(rdev, dst_ring, semaphore);

	}



	for (i = 0; i < RADEON_NUM_RINGS; ++i) {



		/* don't unlock unused rings */

		if (!sync_to[i] && i != dst_ring)

			continue;



		radeon_ring_unlock_commit(rdev, &rdev->ring[i]);

	}



	return 0;



error:

	/* unlock all locks taken so far */

	for (--i; i >= 0; --i) {

		if (sync_to[i] || i == dst_ring) {

			radeon_ring_unlock_undo(rdev, &rdev->ring[i]);

		}

	}

	return r;

}



void radeon_semaphore_free(struct radeon_device *rdev,

			   struct radeon_semaphore *semaphore)

{

drivers/gpu/drm/radeon/radeon_ttm.c

+21 −27
Original line number Diff line number Diff line
@@ -222,8 +222,8 @@ static int radeon_move_blit(struct ttm_buffer_object *bo, 
{

	struct radeon_device *rdev;

	uint64_t old_start, new_start;

	struct radeon_fence *fence;

	int r, i;

	struct radeon_fence *fence, *old_fence;

	int r;



	rdev = radeon_get_rdev(bo->bdev);

	r = radeon_fence_create(rdev, &fence, radeon_copy_ring_index(rdev));
@@ -242,6 +242,7 @@ static int radeon_move_blit(struct ttm_buffer_object *bo, 
		break;

	default:

		DRM_ERROR("Unknown placement %d\n", old_mem->mem_type);

		radeon_fence_unref(&fence);

		return -EINVAL;

	}

	switch (new_mem->mem_type) {
@@ -253,42 +254,35 @@ static int radeon_move_blit(struct ttm_buffer_object *bo, 
		break;

	default:

		DRM_ERROR("Unknown placement %d\n", old_mem->mem_type);

		radeon_fence_unref(&fence);

		return -EINVAL;

	}

	if (!rdev->ring[radeon_copy_ring_index(rdev)].ready) {

		DRM_ERROR("Trying to move memory with ring turned off.\n");

		radeon_fence_unref(&fence);

		return -EINVAL;

	}



	BUILD_BUG_ON((PAGE_SIZE % RADEON_GPU_PAGE_SIZE) != 0);



	/* sync other rings */

	if (rdev->family >= CHIP_R600) {

		for (i = 0; i < RADEON_NUM_RINGS; ++i) {

			/* no need to sync to our own or unused rings */

			if (i == radeon_copy_ring_index(rdev) || !rdev->ring[i].ready)

				continue;

	old_fence = bo->sync_obj;

	if (old_fence && old_fence->ring != fence->ring

	    && !radeon_fence_signaled(old_fence)) {

		bool sync_to_ring[RADEON_NUM_RINGS] = { };

		sync_to_ring[old_fence->ring] = true;



			if (!fence->semaphore) {

		r = radeon_semaphore_create(rdev, &fence->semaphore);

				/* FIXME: handle semaphore error */

				if (r)

					continue;

		if (r) {

			radeon_fence_unref(&fence);

			return r;

		}



			r = radeon_ring_lock(rdev, &rdev->ring[i], 3);

			/* FIXME: handle ring lock error */

			if (r)

				continue;

			radeon_semaphore_emit_signal(rdev, i, fence->semaphore);

			radeon_ring_unlock_commit(rdev, &rdev->ring[i]);



			r = radeon_ring_lock(rdev, &rdev->ring[radeon_copy_ring_index(rdev)], 3);

			/* FIXME: handle ring lock error */

			if (r)

				continue;

			radeon_semaphore_emit_wait(rdev, radeon_copy_ring_index(rdev), fence->semaphore);

			radeon_ring_unlock_commit(rdev, &rdev->ring[radeon_copy_ring_index(rdev)]);

		r = radeon_semaphore_sync_rings(rdev, fence->semaphore,

						sync_to_ring, fence->ring);

		if (r) {

			radeon_fence_unref(&fence);

			return r;

		}

	}