diff --git a/sys/dev/drm/amd/amdgpu/amdgpu_gfx.c b/sys/dev/drm/amd/amdgpu/amdgpu_gfx.c
--- a/sys/dev/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/sys/dev/drm/amd/amdgpu/amdgpu_gfx.c
@@ -208,7 +208,7 @@
 		    * adev->gfx.mec.num_pipe_per_mec
 		    * adev->gfx.mec.num_queue_per_pipe;
 
-	while (queue_bit-- >= 0) {
+	while (queue_bit-- > 0) {
 		if (test_bit(queue_bit, adev->gfx.mec.queue_bitmap))
 			continue;