Re: [PATCH] drm/rockchip: cdn-dp: Fix error handling

[Mark yao]

On 2017å02æ20æ 14:41, Christophe JAILLET wrote:
> Le 20/02/2017 Ã 02:40, Mark yao a Ãcrit :
> > On 2017å02æ20æ 00:59, Christophe JAILLET wrote:
> > > It is likely that both 'clk_disable_unprepare()' should be called if
> > > 'pm_runtime_get_sync()' fails.
> > >
> > > Add a new label for that, because 'err_set_rate' is not meaningful 
> > > in this
> > > case.
> > >
> > >
> > > Fixes: 1a0f7ed3abe2 ("drm/rockchip: cdn-dp: add cdn DP support for 
> > > rk3399")
> > >
> > > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > > ---
> > > Not sure but a 'pm_runtime_get_sync()' is maybe also required in the
> > > 'err_set_rate' path.
> > > ---
> > >   drivers/gpu/drm/rockchip/cdn-dp-core.c | 3 ++-
> > >   1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c 
> > > b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> > > index 9ab67a670885..0fe1ec8b8fb1 100644
> > > --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
> > > +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> > > @@ -111,7 +111,7 @@ static int cdn_dp_clk_enable(struct 
> > > cdn_dp_device *dp)
> > >       ret = pm_runtime_get_sync(dp->dev);
> > >       if (ret < 0) {
> > >           DRM_DEV_ERROR(dp->dev, "cannot get pm runtime %d\n", ret);
> > > -        goto err_pclk;
> > > +        goto err_sync;
> >
> > I think the name err_pm_runtime_get is better.
> > err_sync is not a clear name for the pm_runtime_get_sync.
> I will change it.
>
> > >       }
> > >         reset_control_assert(dp->core_rst);
> > > @@ -133,6 +133,7 @@ static int cdn_dp_clk_enable(struct 
> > > cdn_dp_device *dp)
> > >       return 0;
> > >     err_set_rate:
> > > +err_sync:
> >
> > miss pm_runtime_put, it should be:
> I am wondering if 'pm_runtime_put_sync' should be added, instead.
> We want to revert the 'pm_runtime_get_sync' of line 111. According to 
> the naming of the function, the _sync version looks more logical to me.
> Using ccoccinelle shows that 2/3 of functions calling both 
> 'pm_runtime_get_sync' and 'pm_runtime_get[_sync]' and using the _sync 
> variant.

pm_runtime_get_sync will block until hardware actually done power configure,
we need make sure power is enable before use the hardware, So we should 
use pm_runtime_get_sync at power on.

At power off time, use pm_runtime_put is enough, it can be async, no 
need block.

Thanks.

> Which semantic is the correct one?
>
>
> > err_set_rate:
> >     pm_runtime_put(dp->dev);
> > err_pm_runtime_get:
> >     clk_disable_unprepare(dp->core_clk);
> > err_core_clk:
> >
> > > clk_disable_unprepare(dp->core_clk);
> > >   err_core_clk:
> > >       clk_disable_unprepare(dp->pclk);


--
ïark Yao