[PATCH v2] drm/vc4: Fix pm_runtime_get_sync() usage

[Miaoqian Lin <linmq006@gmail.com>]

If the device is already in a runtime PM enabled state
pm_runtime_get_sync() will return 1, so a test for negative
value should be used to check for errors.

Also, we need to call pm_runtime_put_noidle() when pm_runtime_get_sync()
fails, so use pm_runtime_resume_and_get() instead. this function
will handle this.

Fixes: 4078f5757144 ("drm/vc4: Add DSI driver")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
change in v2:
- switch to pm_runtime_resume_and_get() to fix refcount leak.
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
index 752f921735c6..9d7ffaf6bc70 100644
--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -846,8 +846,8 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder)
 	unsigned long phy_clock;
 	int ret;
 
-	ret = pm_runtime_get_sync(dev);
-	if (ret) {
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
 		DRM_ERROR("Failed to runtime PM enable on DSI%d\n", dsi->variant->port);
 		return;
 	}
-- 
2.17.1