Nouveau - May 2020 - [PATCH] drm/nouveau/dispnv50: fix runtime pm imbalance on error

pm_runtime_get_sync() increments the runtime PM usage counter even
the call returns an error code. Thus a pairing decrement is needed
on the error handling path to keep the counter balanced.

Signed-off-by: Dinghao Liu <dinghao.liu at zju.edu.cn>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 6be9df1820c5..e670756664ff 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1123,8 +1123,10 @@ nv50_mstc_detect(struct drm_connector *connector,
 		return connector_status_disconnected;
 
 	ret = pm_runtime_get_sync(connector->dev->dev);
-	if (ret < 0 && ret != -EACCES)
+	if (ret < 0 && ret != -EACCES) {
+		pm_runtime_put_autosuspend(connector->dev->dev);
 		return connector_status_disconnected;
+	}
 
 	ret = drm_dp_mst_detect_port(connector, ctx, mstc->port->mgr,
 				     mstc->port);
-- 
2.17.1

Hi! Was going through my email and found this from last month, it's a bit
late
and someone might have reviewed/pushed this already but just in case:

Reviewed-by: Lyude Paul <lyude at redhat.com>

On Wed, 2020-05-20 at 18:47 +0800, Dinghao Liu wrote:
> pm_runtime_get_sync() increments the runtime PM usage counter even
> the call returns an error code. Thus a pairing decrement is needed
> on the error handling path to keep the counter balanced.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu at zju.edu.cn>
> ---
>  drivers/gpu/drm/nouveau/dispnv50/disp.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index 6be9df1820c5..e670756664ff 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -1123,8 +1123,10 @@ nv50_mstc_detect(struct drm_connector *connector,
>  		return connector_status_disconnected;
>  
>  	ret = pm_runtime_get_sync(connector->dev->dev);
> -	if (ret < 0 && ret != -EACCES)
> +	if (ret < 0 && ret != -EACCES) {
> +		pm_runtime_put_autosuspend(connector->dev->dev);
>  		return connector_status_disconnected;
> +	}
>  
>  	ret = drm_dp_mst_detect_port(connector, ctx, mstc->port->mgr,
>  				     mstc->port);