gpu: nvgpu: Fix gk20a shutdown issue

With CONFIG_PM_GENERIC_DOMAINS_OF enabled, device reboot
was getting hung while shutting-down gk20a. It was
happening because genpd_dev_pm_detach() was railgating
gk20a while other thread was still accessing it.

So, assigning NULL to dev->pm_domain->detach for gk20a,
so that genpd_dev_pm_detach() is not called during gk20a
shutdown, which will not railgate it.

This patch will be reverted once we have clean shutdown
for gk20a.

Bug 200070810
Bug 200099940

Change-Id: Ie2e89ea01a98a9d4f2f68a3ab07b6923ffa374f6
Signed-off-by: Sumit Singh <sumsingh@nvidia.com>
Reviewed-on: http://git-master/r/735455
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Tested-by: Bharat Nihalani <bnihalani@nvidia.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 6add8441..b8357c76 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -1210,11 +1210,19 @@ static int gk20a_pm_initialise_domain(struct platform_device *pdev)
         struct gk20a_platform *platform = platform_get_drvdata(pdev);
         struct dev_power_governor *pm_domain_gov = NULL;
         struct generic_pm_domain *domain = dev_to_genpd(&pdev->dev);
+        struct device *dev = &pdev->dev;
 
 #ifdef CONFIG_PM_RUNTIME
         if (!platform->can_railgate)
                 pm_domain_gov = &pm_domain_always_on_gov;
 #endif
+        /*
+         * FIXME: We can remove below assignment once we have clean shutdown
+         * for gk20a.
+         */
+        if (dev->pm_domain)
+                dev->pm_domain->detach = NULL;
+
         domain->gov = pm_domain_gov;
 
         if (platform->railgate_delay)