gpu: nvgpu: allow suspend when jobs are pending

We currently check that no job is pending before proceeding with
suspend. This prevents suspend, when we could simply disable and
preempt all channels. Moreover, pending jobs accounting is done
using pm_runtime usage count, which is not updated for GPUs with
pm_runtime disabled (e.g. vgpu).
Replaced the check on pm_runtime usage count, with a check on
gk20a handle usage count. Suspend is allowed when there is no
task inside a busy/idle sequence.

JIRA EVLR-1852

Change-Id: I79e71c8112182622dbd1c7c46cd84befa61a5c4d
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1552348
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 5 insertions, 18 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/module.c b/drivers/gpu/nvgpu/common/linux/module.c
index 51336c51..e7e79949 100644
--- a/drivers/gpu/nvgpu/common/linux/module.c
+++ b/drivers/gpu/nvgpu/common/linux/module.c
@@ -869,21 +869,17 @@ static int gk20a_pm_suspend(struct device *dev)
         struct gk20a_platform *platform = dev_get_drvdata(dev);
         struct gk20a *g = get_gk20a(dev);
         int ret = 0;
-
-        if (g->user_railgate_disabled)
-                gk20a_idle_nosuspend(g);
-
-        if (atomic_read(&dev->power.usage_count) > 1) {
-                ret = -EBUSY;
-                goto fail;
-        }
+        int idle_usage_count = g->user_railgate_disabled ? 1 : 0;
 
         if (!g->power_on)
                 return 0;
 
+        if (nvgpu_atomic_read(&g->usage_count) > idle_usage_count)
+                return -EBUSY;
+
         ret = gk20a_pm_runtime_suspend(dev);
         if (ret)
-                goto fail;
+                return ret;
 
         if (platform->suspend)
                 platform->suspend(dev);
@@ -891,12 +887,6 @@ static int gk20a_pm_suspend(struct device *dev)
         g->suspended = true;
 
         return 0;
-
-fail:
-        if (g->user_railgate_disabled)
-                gk20a_busy_noresume(g);
-
-        return ret;
 }
 
 static int gk20a_pm_resume(struct device *dev)
@@ -904,9 +894,6 @@ static int gk20a_pm_resume(struct device *dev)
         struct gk20a *g = get_gk20a(dev);
         int ret = 0;
 
-        if (g->user_railgate_disabled)
-                gk20a_busy_noresume(g);
-
         if (!g->suspended)
                 return 0;