diff --git a/inc/rk_mpi.h b/inc/rk_mpi.h
index 55ebb064..76ace259 100644
--- a/inc/rk_mpi.h
+++ b/inc/rk_mpi.h
@@ -85,6 +85,8 @@ typedef enum {
     MPP_ENC_GETCFG,
     MPP_ENC_SETFORMAT,
     MPP_ENC_SETIDRFRAME,
+
+    MPI_CMD_BUTT,
 } MpiCmd;
 
 
diff --git a/mpp/legacy/vpu_api_legacy.cpp b/mpp/legacy/vpu_api_legacy.cpp
index 5bdd8d5c..35ee4d7e 100644
--- a/mpp/legacy/vpu_api_legacy.cpp
+++ b/mpp/legacy/vpu_api_legacy.cpp
@@ -254,7 +254,7 @@ RK_S32 VpuApi::control(VpuCodecContext *ctx, VPU_API_CMD cmd, void *param)
         return 0;
     }
 
-    MpiCmd mpicmd = -1;
+    MpiCmd mpicmd = MPI_CMD_BUTT;
     switch (cmd) {
     case VPU_API_SET_VPUMEM_CONTEXT: {
         mpicmd = MPP_DEC_SET_EXT_BUF_GROUP;
@@ -278,7 +278,7 @@ RK_S32 VpuApi::control(VpuCodecContext *ctx, VPU_API_CMD cmd, void *param)
     }
 
     RK_S32 ret = -1;
-    if (mpicmd >= 0)
+    if (mpicmd < MPI_CMD_BUTT)
         ret = mpi->control(mpp_ctx, (MpiCmd)mpicmd, (MppParam)param);
 
     mpp_log_f("ok\n");