diff --git a/drivers/gpu/nvgpu/common/sim.c b/drivers/gpu/nvgpu/common/sim.c
index 8261f2702..618e8ffb0 100644
--- a/drivers/gpu/nvgpu/common/sim.c
+++ b/drivers/gpu/nvgpu/common/sim.c
@@ -28,6 +28,7 @@
 #include <nvgpu/hw_sim.h>
 #include <nvgpu/sim.h>
 #include <nvgpu/utils.h>
+#include <nvgpu/bug.h>
 
 #include "gk20a/gk20a.h"
 
@@ -215,7 +216,7 @@ static int issue_rpc_and_wait(struct gk20a *g)
 	return 0;
 }
 
-static int nvgpu_sim_esc_readl(struct gk20a *g,
+static void nvgpu_sim_esc_readl(struct gk20a *g,
 		char *path, u32 index, u32 *data)
 {
 	int err;
@@ -232,9 +233,12 @@ static int nvgpu_sim_esc_readl(struct gk20a *g,
 
 	err = issue_rpc_and_wait(g);
 
-	if (!err)
+	if (err == 0) {
 		memcpy(data, sim_msg_param(g, data_offset), sizeof(u32));
-	return err;
+	} else {
+		*data = 0xffffffff;
+		WARN(1, "issue_rpc_and_wait failed err=%d", err);
+	}
 }
 
 static void nvgpu_sim_init_late(struct gk20a *g)
diff --git a/drivers/gpu/nvgpu/common/sim_pci.c b/drivers/gpu/nvgpu/common/sim_pci.c
index edf2a4019..5f2344b40 100644
--- a/drivers/gpu/nvgpu/common/sim_pci.c
+++ b/drivers/gpu/nvgpu/common/sim_pci.c
@@ -27,6 +27,7 @@
 #include <nvgpu/sim.h>
 #include <nvgpu/io.h>
 #include <nvgpu/utils.h>
+#include <nvgpu/bug.h>
 
 #include "gk20a/gk20a.h"
 
@@ -183,7 +184,7 @@ static int issue_rpc_and_wait(struct gk20a *g)
 	return 0;
 }
 
-static int nvgpu_sim_esc_readl(struct gk20a *g,
+static void nvgpu_sim_esc_readl(struct gk20a *g,
 		char *path, u32 index, u32 *data)
 {
 	int err;
@@ -200,9 +201,12 @@ static int nvgpu_sim_esc_readl(struct gk20a *g,
 
 	err = issue_rpc_and_wait(g);
 
-	if (!err)
+	if (err == 0) {
 		memcpy(data, sim_msg_param(g, data_offset + 0xc), sizeof(u32));
-	return err;
+	} else {
+		*data = 0xffffffff;
+		WARN(1, "issue_rpc_and_wait failed err=%d", err);
+	}
 }
 
 static void nvgpu_sim_init_late(struct gk20a *g)
diff --git a/drivers/gpu/nvgpu/include/nvgpu/sim.h b/drivers/gpu/nvgpu/include/nvgpu/sim.h
index fe8e8ac6e..41cee8d09 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/sim.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/sim.h
@@ -36,7 +36,7 @@ struct sim_nvgpu {
 	struct nvgpu_mem msg_bfr;
 	void (*sim_init_late)(struct gk20a *);
 	void (*remove_support)(struct gk20a *);
-	int (*esc_readl)(
+	void (*esc_readl)(
 		struct gk20a *g, char *path, u32 index, u32 *data);
 };
 #ifdef __KERNEL__