Hi Alexander, There are large amounts of cases that assume pm_runtime_get_sync() will modify runtime PM usage counter on error. Fixing this in PM subsystem will influence all callers of pm_runtime_get_sync() and introduce new bugs. Therefore I think the better solution is to fix misused cases individually. Dinghao > Hello Dinghao, > > On Wed, 2020-05-20 at 21:29 +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. > > I believe, this is the wrong place for such kind of fix. > pm_runtime_get_sync() has obviously a broken semantics with regards to > your observation but no other driver does what you propose. > I think the proper fix belong into PM subsystem, please take a look > onto commit 15bcb91d7e60 "PM / Runtime: Implement autosuspend support". > > > Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx> > > --- > > drivers/char/hw_random/ks-sa-rng.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/char/hw_random/ks-sa-rng.c b/drivers/char/hw_random/ks-sa-rng.c > > index e2330e757f1f..85c81da4a8af 100644 > > --- a/drivers/char/hw_random/ks-sa-rng.c > > +++ b/drivers/char/hw_random/ks-sa-rng.c > > @@ -244,6 +244,7 @@ static int ks_sa_rng_probe(struct platform_device *pdev) > > ret = pm_runtime_get_sync(dev); > > if (ret < 0) { > > dev_err(dev, "Failed to enable SA power-domain\n"); > > + pm_runtime_put_sync(dev); > > pm_runtime_disable(dev); > > return ret; > > } > -- > Alexander Sverdlin. >