2 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 156d33ed..b921be7c 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -262,6 +262,14 @@ static const struct file_operations gk20a_sched_ops = {
         .read = gk20a_sched_dev_read,
 };
 
+void __nvgpu_check_gpu_state(struct gk20a *g)
+{
+        u32 boot_0 = readl(g->regs + mc_boot_0_r());
+
+        if (boot_0 == 0xffffffff)
+                pr_err("nvgpu: GPU has disappeared from bus!!\n");
+}
+
 static inline void sim_writel(struct gk20a *g, u32 r, u32 v)
 {
         writel(v, g->sim.regs+r);
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index 144cb37d..a4cbb4b2 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -1111,6 +1111,8 @@ void gk20a_init_clk_ops(struct gpu_ops *gops);
 int gk20a_lockout_registers(struct gk20a *g);
 int gk20a_restore_registers(struct gk20a *g);
 
+void __nvgpu_check_gpu_state(struct gk20a *g);
+
 static inline void gk20a_writel(struct gk20a *g, u32 r, u32 v)
 {
         gk20a_dbg(gpu_dbg_reg, " r=0x%x v=0x%x", r, v);
@@ -1120,7 +1122,12 @@ static inline void gk20a_writel(struct gk20a *g, u32 r, u32 v)
 static inline u32 gk20a_readl(struct gk20a *g, u32 r)
 {
         u32 v = readl(g->regs + r);
+
+        if (v == 0xffffffff)
+                __nvgpu_check_gpu_state(g);
+
         gk20a_dbg(gpu_dbg_reg, " r=0x%x v=0x%x", r, v);
+
         return v;
 }
 static inline void gk20a_writel_check(struct gk20a *g, u32 r, u32 v)