diff --git a/exynos/exynos_fimg2d.c b/exynos/exynos_fimg2d.c
index fbc77a3d..5873fe79 100644
--- a/exynos/exynos_fimg2d.c
+++ b/exynos/exynos_fimg2d.c
@@ -18,6 +18,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
+#include <assert.h>
 
 #include <sys/mman.h>
 #include <linux/stddef.h>
@@ -172,8 +173,11 @@ static int g2d_validate_blending_op(
  * @ctx: a pointer to g2d_context structure.
  * @cmd: command data.
  * @value: value data.
+ *
+ * The caller has to make sure that the commands buffers have enough space
+ * left to hold the command. Use g2d_check_space() to ensure this.
  */
-static int g2d_add_cmd(struct g2d_context *ctx, unsigned long cmd,
+static void g2d_add_cmd(struct g2d_context *ctx, unsigned long cmd,
 			unsigned long value)
 {
 	switch (cmd & ~(G2D_BUF_USERPTR)) {
@@ -183,28 +187,20 @@ static int g2d_add_cmd(struct g2d_context *ctx, unsigned long cmd,
 	case DST_PLANE2_BASE_ADDR_REG:
 	case PAT_BASE_ADDR_REG:
 	case MASK_BASE_ADDR_REG:
-		if (ctx->cmd_buf_nr >= G2D_MAX_GEM_CMD_NR) {
-			fprintf(stderr, "Overflow cmd_gem size.\n");
-			return -EINVAL;
-		}
+		assert(ctx->cmd_buf_nr < G2D_MAX_GEM_CMD_NR);
 
 		ctx->cmd_buf[ctx->cmd_buf_nr].offset = cmd;
 		ctx->cmd_buf[ctx->cmd_buf_nr].data = value;
 		ctx->cmd_buf_nr++;
 		break;
 	default:
-		if (ctx->cmd_nr >= G2D_MAX_CMD_NR) {
-			fprintf(stderr, "Overflow cmd size.\n");
-			return -EINVAL;
-		}
+		assert(ctx->cmd_nr < G2D_MAX_CMD_NR);
 
 		ctx->cmd[ctx->cmd_nr].offset = cmd;
 		ctx->cmd[ctx->cmd_nr].data = value;
 		ctx->cmd_nr++;
 		break;
 	}
-
-	return 0;
 }
 
 /*