pm_runtime_get_sync() increments the runtime PM usage counter
even when it returns an error code. However, users of
dsi_runtime_get(), a direct wrapper of pm_runtime_get_sync(),
assume that PM usage counter will not change on error. Thus a
pairing decrement is needed on the error handling path to keep
the counter balanced.

Fixes: 4fbafaf371be7 ("OMAP: DSS2: Use PM runtime & HWMOD support")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/gpu/drm/omapdrm/dss/dsi.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
index eeccf40bae41..973bfa14a104 100644
--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -1112,8 +1112,11 @@ static int dsi_runtime_get(struct dsi_data *dsi)
 	DSSDBG("dsi_runtime_get\n");
 
 	r = pm_runtime_get_sync(dsi->dev);
-	WARN_ON(r < 0);
-	return r < 0 ? r : 0;
+	if (WARN_ON(r < 0)) {
+		pm_runtime_put_noidle(dsi->dev);
+		return r;
+	}
+	return 0;
 }
 
 static void dsi_runtime_put(struct dsi_data *dsi)
-- 
2.17.1