[PATCH] drm/amdgpu: execute amdgpu_ring_patch_cond_exec() only for valid job

[Shirish S]

issue:
BUG_ON(ring->ring[offset] != 0x55aa55aa) is hit on resume from
S3 state.

fix & analysis:

fix is  to check for valid job, which in continuation to the below patch:
113890e drm/amdgpu: cond_exec only for schedule with a job

Since cond_exec is not initialised if there is no job,
0x55aa55aa is not written to ring, as a result in
patch_cond_exec callback, BUG_ON is hit where it checks for the
same 0x55aa55aa value in register.

Signed-off-by: Shirish S <shirish.s at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
index 31f8170..3381ada 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
@@ -249,7 +249,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 				       fence_flags | AMDGPU_FENCE_FLAG_64BIT);
 	}
 
-	if (patch_offset != ~0 && ring->funcs->patch_cond_exec)
+	if (job && patch_offset != ~0 && ring->funcs->patch_cond_exec)
 		amdgpu_ring_patch_cond_exec(ring, patch_offset);
 
 	ring->current_ctx = fence_ctx;
-- 
2.7.4