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    SubjectRe: [PATCH v2 03/19] PM / devfreq: tegra: Don't ignore clk errors
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    Hi,

    On 19. 4. 15. 오후 11:54, Dmitry Osipenko wrote:
    > The clk_set_min_rate() could fail and in this case clk_set_rate() sets
    > rate to 0, which may drop EMC rate to minimum and make machine very
    > difficult to use.
    >
    > Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
    > ---
    > drivers/devfreq/tegra-devfreq.c | 10 ++++++++--
    > 1 file changed, 8 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
    > index 0c0909fba545..69581c9082d4 100644
    > --- a/drivers/devfreq/tegra-devfreq.c
    > +++ b/drivers/devfreq/tegra-devfreq.c
    > @@ -487,6 +487,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
    > struct tegra_devfreq *tegra = dev_get_drvdata(dev);
    > struct dev_pm_opp *opp;
    > unsigned long rate;
    > + int err;
    >
    > opp = devfreq_recommended_opp(dev, freq, flags);
    > if (IS_ERR(opp)) {
    > @@ -496,8 +497,13 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
    > rate = dev_pm_opp_get_freq(opp);
    > dev_pm_opp_put(opp);
    >
    > - clk_set_min_rate(tegra->emc_clock, rate);
    > - clk_set_rate(tegra->emc_clock, 0);
    > + err = clk_set_min_rate(tegra->emc_clock, rate);
    > + if (err)
    > + return err;
    > +
    > + err = clk_set_rate(tegra->emc_clock, 0);
    > + if (err)

    Why don't you restore the previous minimum clock for tegra->emc_clock
    when failed to execute 'clk_set_rate(tegra->emc_clock, 0);'?

    I think that if you control the restoring the previous minimum clock,
    it is more nice to handle the error handling.

    > + return err;
    >
    > return 0;
    > }
    >


    --
    Best Regards,
    Chanwoo Choi
    Samsung Electronics

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