1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/gr_gm20b.c b/drivers/gpu/nvgpu/gm20b/gr_gm20b.c
index d00181af..dacef784 100644
--- a/drivers/gpu/nvgpu/gm20b/gr_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/gr_gm20b.c
@@ -1468,10 +1468,15 @@ int gm20b_gr_set_mmu_debug_mode(struct gk20a *g,
                         gr_gpcs_pri_mmu_debug_ctrl_debug_disabled_f(),
         };
         int err;
+        struct tsg_gk20a *tsg = tsg_gk20a_from_ch(ch);
+
+        if (tsg == NULL) {
+                return enable ? -EINVAL : 0;
+        }
 
         err = gr_gk20a_exec_ctx_ops(ch, &ctx_ops, 1, 1, 0, NULL);
         if (err != 0) {
-                nvgpu_err(g, "Failed to access register");
+                nvgpu_err(g, "update MMU debug mode failed");
         }
         return err;
 }