[PATCH 3.16 018/346] drm/nouveau: Don't leak runtime pm ref on driver unload

[Ben Hutchings]

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <lukas@xxxxxxxxx>

commit c1b16b45607976c76a3c41b8a319172b8b83f996 upstream.

nouveau_drm_load() calls pm_runtime_put() if nouveau_runtime_pm != 0,
but nouveau_drm_unload() calls pm_runtime_get_sync() unconditionally.
We therefore leak a runtime pm ref whenever nouveau is loaded with
runpm=0 and then unloaded. The GPU will subsequently never runtime
suspend even if nouveau is loaded again with runpm=1.

Fix by taking the runtime pm ref under the same condition that it was
released on driver load.

Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
Reported-by: Karol Herbst <karolherbst@xxxxxxxxx>
Tested-by: Karol Herbst <karolherbst@xxxxxxxxx>
Tested-by: Peter Wu <peter@xxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/1544b82007037601fbc510b1a50edc56c529e75f.1465392124.git.lukas@xxxxxxxxx
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -472,7 +472,10 @@ nouveau_drm_unload(struct drm_device *de
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 
-	pm_runtime_get_sync(dev->dev);
+	if (nouveau_runtime_pm != 0) {
+		pm_runtime_get_sync(dev->dev);
+	}
+
 	nouveau_fbcon_fini(dev);
 	nouveau_accel_fini(drm);
 	nouveau_hwmon_fini(dev);