linux-kernel - Re: [PATCH 4/5] memstick: rtsx_usb_ms: Support runtime power management

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Date:   Wed, 1 Aug 2018 15:29:24 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        "Bauer.Chen" <bauer.chen@...ltek.com>, ricky_wu@...ltek.com,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux USB List <linux-usb@...r.kernel.org>
Subject: Re: [PATCH 4/5] memstick: rtsx_usb_ms: Support runtime power management

[...]

> -#ifdef CONFIG_PM_SLEEP
> -static int rtsx_usb_ms_suspend(struct device *dev)
> +#ifdef CONFIG_PM
> +static int rtsx_usb_ms_runtime_suspend(struct device *dev)
>  {
>         struct rtsx_usb_ms *host = dev_get_drvdata(dev);
>         struct memstick_host *msh = host->msh;
>
> -       dev_dbg(ms_dev(host), "--> %s\n", __func__);
> -
> +       host->suspend = true;
>         memstick_suspend_host(msh);

I missed this one. Does this really work? To me, this looks like doing
things upside-down.

To suspend the host, you first need to runtime resume it, because
mmc_suspend_host() calls into one of the host ops and my touch the
device, right?

If you want to suspend the host (actually the naming is wrong, as it's
about suspending/power-iff the memstick card), that should be done via
when the memstick core finds that the card is removed or during system
wide suspend.

> +
>         return 0;
>  }
>
> -static int rtsx_usb_ms_resume(struct device *dev)
> +static int rtsx_usb_ms_runtime_resume(struct device *dev)
>  {
>         struct rtsx_usb_ms *host = dev_get_drvdata(dev);
>         struct memstick_host *msh = host->msh;
>
> -       dev_dbg(ms_dev(host), "--> %s\n", __func__);
> -
>         memstick_resume_host(msh);

According to the above, this seems not correct to me.

> +       host->suspend = false;
> +       schedule_delayed_work(&host->poll_card, 100);
> +
>         return 0;
>  }
> -#endif /* CONFIG_PM_SLEEP */
>

[...]

Kind regards
Uffe