gpu: nvgpu: gk20a: fix elpg sysfs control

bug 200200943

When we enable ELPG through sysfs there is a possibility of
refcounting twice as enable ELPG function is done in
scheduled work during rail gating exit and also called from sysfs
write. Just updating elpg enable/disable flag is good enough
as ELPG code uses it during rail gating exit

Change-Id: Ibb267d4ce30b9848abcde29882b90d884ef213bb
Signed-off-by: Vijayakumar <vsubbu@nvidia.com>
Reviewed-on: http://git-master/r/1149587
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>

1 files changed, 18 insertions, 16 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
index 29c92398..b68073af 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
@@ -425,23 +425,25 @@ static ssize_t elpg_enable_store(struct device *dev,
         if (kstrtoul(buf, 10, &val) < 0)
                 return -EINVAL;
 
-        /*
-         * Since elpg is refcounted, we should not unnecessarily call
-         * enable/disable if it is already so.
-         */
-        err = gk20a_busy(g->dev);
-        if (err)
-                return -EAGAIN;
-
-        if (val && !g->elpg_enabled) {
-                g->elpg_enabled = true;
-                gk20a_pmu_enable_elpg(g);
-        } else if (!val && g->elpg_enabled) {
-                g->elpg_enabled = false;
-                gk20a_pmu_disable_elpg(g);
+        if (!g->power_on) {
+                g->elpg_enabled = val ? true : false;
+        } else {
+                err = gk20a_busy(g->dev);
+                if (err)
+                        return -EAGAIN;
+                /*
+                 * Since elpg is refcounted, we should not unnecessarily call
+                 * enable/disable if it is already so.
+                 */
+                if (val && !g->elpg_enabled) {
+                        g->elpg_enabled = true;
+                        gk20a_pmu_enable_elpg(g);
+                } else if (!val && g->elpg_enabled) {
+                        g->elpg_enabled = false;
+                        gk20a_pmu_disable_elpg(g);
+                }
+                gk20a_idle(g->dev);
         }
-        gk20a_idle(g->dev);
-
         dev_info(dev, "ELPG is %s.\n", g->elpg_enabled ? "enabled" :
                         "disabled");