Re: [PATCH] devfreq: rk3399_dmc: Fix duplicated opp table on reload.

Enric Balletbo Serra
2018-07-17T13:18:09Z

Missatge de Chanwoo Choi <cw00.choi@samsung.com> del dia dc., 20 de
juny 2018 a les 2:50:
>
> Hi Enric,
>
> On 2018년 06월 19일 17:07, Enric Balletbo i Serra wrote:
> > Hi Chanwoo,
> >
> > On 19/06/18 06:18, Chanwoo Choi wrote:
> >> Hi Enric,
> >>
> >> On 2018년 06월 18일 18:10, Enric Balletbo Serra wrote:
> >>> Hi Chanwoo,
> >>>
> >>> Missatge de Chanwoo Choi <cwchoi00@gmail.com> del dia dg., 17 de juny
> >>> 2018 a les 5:23:
> >>>>
> >>>> Hi Enric,
> >>>>
> >>>> 2018-06-16 0:12 GMT+09:00 Enric Balletbo i Serra <enric.balletbo@collabora.com>:
> >>>>> The opp table is not removed when the driver is unloaded neither when
> >>>>> there is an error within probe, so if the driver is reloaded the opp
> >>>>> core shows the following warning:
> >>>>>
> >>>>> rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
> >>>>> 200000000, volt: 900000, enabled: 1. New: freq: 200000000,
> >>>>> volt: 900000, enabled: 1
> >>>>> rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
> >>>>> 400000000, volt: 900000, enabled: 1. New: freq: 400000000,
> >>>>> volt: 900000, enabled: 1
> >>>>> rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
> >>>>> 666000000, volt: 900000, enabled: 1. New: freq: 666000000,
> >>>>> volt: 900000, enabled: 1
> >>>>> rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
> >>>>> 800000000, volt: 900000, enabled: 1. New: freq: 800000000,
> >>>>> volt: 900000, enabled: 1
> >>>>> rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
> >>>>> 928000000, volt: 900000, enabled: 1. New: freq: 928000000,
> >>>>> volt: 900000, enabled: 1
> >>>>>
> >>>>> This patch fixes the error path in the probe function and adds a .remove
> >>>>> function to properly cleanup the opp table on unloading.
> >>>>>
> >>>>> Fixes: 5a893e31a636c (PM / devfreq: rockchip: add devfreq driver for rk3399 dmc)
> >>>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >>>>> ---
> >>>>>
> >>>>> drivers/devfreq/rk3399_dmc.c | 31 +++++++++++++++++++++++++++----
> >>>>> 1 file changed, 27 insertions(+), 4 deletions(-)
> >>>>>
> >>>>> diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
> >>>>> index d5c03e5abe13..e795ad2b3f6b 100644
> >>>>> --- a/drivers/devfreq/rk3399_dmc.c
> >>>>> +++ b/drivers/devfreq/rk3399_dmc.c
> >>>>> @@ -375,8 +375,10 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> >>>>> data->rate = clk_get_rate(data->dmc_clk);
> >>>>>
> >>>>> opp = devfreq_recommended_opp(dev, &data->rate, 0);
> >>>>> - if (IS_ERR(opp))
> >>>>> - return PTR_ERR(opp);
> >>>>> + if (IS_ERR(opp)) {
> >>>>> + ret = PTR_ERR(opp);
> >>>>> + goto err_free_opp;
> >>>>> + }
> >>>>>
> >>>>> data->rate = dev_pm_opp_get_freq(opp);
> >>>>> data->volt = dev_pm_opp_get_voltage(opp);
> >>>>> @@ -388,13 +390,33 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> >>>>> &rk3399_devfreq_dmc_profile,
> >>>>> DEVFREQ_GOV_SIMPLE_ONDEMAND,
> >>>>> &data->ondemand_data);
> >>>>> - if (IS_ERR(data->devfreq))
> >>>>> - return PTR_ERR(data->devfreq);
> >>>>> + if (IS_ERR(data->devfreq)) {
> >>>>> + ret = PTR_ERR(data->devfreq);
> >>>>> + goto err_free_opp;
> >>>>> + }
> >>>>> +
> >>>>> devm_devfreq_register_opp_notifier(dev, data->devfreq);
> >>>>>
> >>>>> data->dev = dev;
> >>>>> platform_set_drvdata(pdev, data);
> >>>>>
> >>>>> + return 0;
> >>>>
> >>>> It looks strange. Because rk3399_dmcfreq_probe() already include
> >>>> 'return 0' when success.
> >>>> What is the base commit of this patch?
> >>>>
> >>>
> >>> Sorry, I am not sure I understand your question, If I am not answering
> >>> below could you rephrase?
> >>
> >> When I check the rk3399_dmcfreq_probe()[1], as I commented,
> >> rk3399_dmcfreq_probe() already 'return 0' after platform_set_drvdata().
> >> You can check it on link[1].
> >> [1] https://elixir.bootlin.com/linux/v4.18-rc1/source/drivers/devfreq/rk3399_dmc.c#L443
> >>
> >> But, this patch add new '+ return 0;' line again in rk3399_dmcfreq_probe().
> >> So, just I asked what is base commit of this patch.
> >>
> >
> > I think that this is just how git did the diff and if you only look at the diff
> > is a bit confusing, if you apply the patch on top of mainline you will see that
> > there is only one return 0 in the probe function.
>
> Anyway, when I applied it to git, there is no problem.
> Just I have never seen such a case and asked a question.
> Don't care about this anymore. Thanks.
>
> >
> > + return 0; (this new return ...)
> > +
> > +err_free_opp:
> > + dev_pm_opp_of_remove_table(&pdev->dev);
> > + return ret;
> > +}
> > +
> > +static int rk3399_dmcfreq_remove(struct platform_device *pdev)
> > +{
> > + struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(&pdev->dev);
> > +
> > + /*
> > + * Before remove the opp table we need to unregister the opp notifier.
> > + */
> > + devm_devfreq_unregister_opp_notifier(dmcfreq->dev, dmcfreq->devfreq);
> > + dev_pm_opp_of_remove_table(dmcfreq->dev);
> > +
> > return 0; (was this before the patch, but now is in another function)
> >
> > Cheers,
> > Enric
> >
> >>>
> >>> So, once the opp table is added we need an error path to free it if an
> >>> error occurs later. When the probe returns 0, we need to free the opp
> >>> table when we remove the module.
> >>>
> >>>> [snip]
> >>>>
> >>>> Anyway, if probe fail, device driver have to remove registered OPP table.
> >>>> Looks good to me.
> >>>>
> >>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> >>>>

A gentle ping, although is a fix I think is late and not enough
critical to be merged in this release cycle, there is a chance this
can be queued for 4.19?

Thanks,
Enric

> >>>
> >>> Thanks,
> >>> Enric
> >>>
> >>>> --
> >>>> Best Regards,
> >>>> Chanwoo Choi
> >>>> Samsung Electronics
> >>>
> >>>
> >>>
> >>
> >>
> >
> >
> >
>
>
> --
> Best Regards,
> Chanwoo Choi
> Samsung Electronics