linux-kernel - Re: [PATCH 5/6] devfreq: rk3399_dmc: do not print error when get supply and clk defer.

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Date:   Mon, 23 Apr 2018 10:37:28 -0300
From:   Ezequiel Garcia <ezequiel@...labora.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Myungjoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        Heiko Stuebner <heiko@...ech.de>,
        Linux PM <linux-pm@...r.kernel.org>,
        Derek Basehore <dbasehore@...omium.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Doug Anderson <dianders@...gle.com>, groek@...gle.com,
        kernel@...labora.com, Lin Huang <hl@...k-chips.com>,
        Chanwoo Choi <cw00.choi@...sung.com>
Subject: Re: [PATCH 5/6] devfreq: rk3399_dmc: do not print error when get
 supply and clk defer.

On Mon, 2018-04-23 at 12:44 +0200, Ulf Hansson wrote:
> On 19 April 2018 at 12:40, Enric Balletbo i Serra
> <enric.balletbo@...labora.com> wrote:
> > From: Lin Huang <hl@...k-chips.com>
> > 
> > We just return -EPROBE_DEFER error code to caller and do not
> > print error message when try to get center logic regulator
> > and DMC clock defer.
> > 
> > Signed-off-by: Lin Huang <hl@...k-chips.com>
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> > ---
> > 
> >  drivers/devfreq/rk3399_dmc.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
> > index 44a379657cd5..5bfca028eaaf 100644
> > --- a/drivers/devfreq/rk3399_dmc.c
> > +++ b/drivers/devfreq/rk3399_dmc.c
> > @@ -308,12 +308,18 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> > 
> >         data->vdd_center = devm_regulator_get(dev, "center");
> >         if (IS_ERR(data->vdd_center)) {
> > +               if (PTR_ERR(data->vdd_center) == -EPROBE_DEFER)
> > +                       return -EPROBE_DEFER;
> > +
> >                 dev_err(dev, "Cannot get the regulator \"center\"\n");
> 
> Doesn't the clock core already print an error message for this?
> 

s/clock/regulator?

> Maybe a better way is simply to drop the printing instead of trying to
> have a special case for it?
> 

I don't think so.

If you remove this print you: i) might get a print from the core,
or ii) maybe not because of some path without a print.

And even if you do get an error, it might not relate exactly to the
driver that requested the resource, because you might be printing
via pr_xxx, from a context without a struct dev to use dev_xxx.

> >                 return PTR_ERR(data->vdd_center);
> >         }
> > 
> >         data->dmc_clk = devm_clk_get(dev, "dmc_clk");
> >         if (IS_ERR(data->dmc_clk)) {
> > +               if (PTR_ERR(data->dmc_clk) == -EPROBE_DEFER)
> > +                       return -EPROBE_DEFER;
> > +
> >                 dev_err(dev, "Cannot get the clk dmc_clk\n");
> >                 return PTR_ERR(data->dmc_clk);
> >         };
> > --
> > 2.17.0
> > 
> 
> Kind regards
> Uffe
>