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SubjectRe: [PATCH v3 04/16] PM / devfreq: tegra: Don't ignore clk errors
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On 19. 4. 18. 오전 7:29, 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 | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
> index 7d7b9a5895b2..c7428c5eee23 100644
> --- a/drivers/devfreq/tegra-devfreq.c
> +++ b/drivers/devfreq/tegra-devfreq.c
> @@ -484,8 +484,10 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
> u32 flags)
> {
> struct tegra_devfreq *tegra = dev_get_drvdata(dev);
> + struct devfreq *devfreq = tegra->devfreq;
> struct dev_pm_opp *opp;
> unsigned long rate;
> + int err;
>
> opp = devfreq_recommended_opp(dev, freq, flags);
> if (IS_ERR(opp)) {
> @@ -495,10 +497,20 @@ 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)
> + goto restore_min_rate;
>
> return 0;
> +
> +restore_min_rate:
> + clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
> +
> + return err;
> }
>
> static int tegra_devfreq_get_dev_status(struct device *dev,
>

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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