Hi Maxime, > -----Original Message----- > From: Biju Das > Sent: Monday, July 8, 2024 10:01 AM > Subject: RE: [PATCH] drm: renesas: shmobile: shmo_drm_crtc: Fix PM imbalance > if RPM_ACTIVE is true > > Hi Maxime, > > > -----Original Message----- > > From: Maxime Ripard <mrip...@kernel.org> > > Sent: Monday, July 8, 2024 9:54 AM > > Subject: Re: [PATCH] drm: renesas: shmobile: shmo_drm_crtc: Fix PM > > imbalance if RPM_ACTIVE is true > > > > Hi, > > > > On Mon, Jul 08, 2024 at 09:27:09AM GMT, Biju Das wrote: > > > The pm_runtime_resume_and_get() returns 1 if RPM is active, in this > > > case it won't call a put. This will result in PM imbalance as it > > > treat this as an error and propagate this to caller and the caller > > > never calls corresponding put(). Fix this issue by checking error > > > condition only. > > > > > > Signed-off-by: Biju Das <biju.das...@bp.renesas.com> > > > --- > > > drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c > > > b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c > > > index 2e2f37b9d0a4..42a5d6876bec 100644 > > > --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c > > > +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c > > > @@ -208,7 +208,7 @@ static void shmob_drm_crtc_atomic_enable(struct > > > drm_crtc *crtc, > > > int ret; > > > > > > ret = pm_runtime_resume_and_get(dev); > > > - if (ret) > > > + if (ret < 0) > > > return; > > > > The documentation of pm_runtime_resume_and_get says that: > > > > Resume @dev synchronously and if that is successful, increment its > > runtime PM usage counter. Return 0 if the runtime PM usage counter of > > @dev has been incremented or a negative error code otherwise. > > > > So it looks like it can't return 1, ever. Are you sure you're not > > confusing pm_runtime_resume_and_get with pm_runtime_get? > > It should be ret < 0 as ret = 1 corresponds to RPM_ACTIVE and the API does > not call put() when ret = > 1; see [1] and [2] > > [1] > https://elixir.bootlin.com/linux/v6.10-rc6/source/drivers/base/power/runtime.c#L778 > > [2] > https://elixir.bootlin.com/linux/v6.10-rc6/source/include/linux/pm_runtime.h#L431 > > Am I miss anything? Please let me know.
the code for pm_runtime_resume_and_get() seems correct. Sorry for the noisy patch. https://elixir.bootlin.com/linux/latest/source/include/linux/pm_runtime.h#L436 Cheers, Biju
