WAR: gpu: nvgpu: gp10b: disable railgate for K4.4

This is done to mask a race issue seen where power refcount
is zero during ISR or bottom half.

Bug 200198908

Change-Id: I0a8ed774cd4fda9db65429b5aad03c5e001ff666
Signed-off-by: Bharat Nihalani <bnihalani@nvidia.com>
Reviewed-on: http://git-master/r/1162314
Reviewed-by: Juha Tukkinen <jtukkinen@nvidia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gp10b/platform_gp10b_tegra.c b/drivers/gpu/nvgpu/gp10b/platform_gp10b_tegra.c
index b9f50817..b844875b 100644
--- a/drivers/gpu/nvgpu/gp10b/platform_gp10b_tegra.c
+++ b/drivers/gpu/nvgpu/gp10b/platform_gp10b_tegra.c
@@ -371,7 +371,12 @@ struct gk20a_platform t18x_gpu_tegra_platform = {
         .railgate_delay         = 500,
 
         /* power management configuration */
+        /* WAR: Rail-gating GPU causes hangs on kernel-4.4 */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0)
         .can_railgate           = true,
+#else
+        .can_railgate           = false,
+#endif
         .enable_elpg            = true,
         .can_elpg               = true,
         .enable_blcg            = true,