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SubjectRe: [PATCH RESEND] phy: phy-twl4030-usb: fix denied runtime access
Hi Andreas,

On Mon, Sep 17, 2018 at 07:22:54AM +0200, Andreas Kemnade wrote:
> When runtime is not enabled, pm_runtime_get_sync() returns -EACCESS,
> the counter will be incremented but the resume callback not called,
> so enumeration and charging will not start properly.
> To avoid that happen, wait and try again later.
>
> Practically this happens when the device is woken up from suspend by
> plugging in usb.
>
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> ---
> drivers/phy/ti/phy-twl4030-usb.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/phy/ti/phy-twl4030-usb.c b/drivers/phy/ti/phy-twl4030-usb.c
> index a44680d64f9b..1f3cf4e48383 100644
> --- a/drivers/phy/ti/phy-twl4030-usb.c
> +++ b/drivers/phy/ti/phy-twl4030-usb.c
> @@ -552,6 +552,15 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl)
>
> status = twl4030_usb_linkstat(twl);
>
> + /* we might get here too early when runtime is not ready yet
> + * and we will get an EACCESS later, so try again later
> + */

How exactly can this happen? What disables (and later re-enables)
runtime PM? How can we guarantee that the interrupt will be
re-triggered?

> + if (!pm_runtime_enabled(twl->dev)) {
> + cancel_delayed_work(&twl->id_workaround_work);
> + schedule_delayed_work(&twl->id_workaround_work, HZ);
> + return IRQ_HANDLED;
> + }
> +
> mutex_lock(&twl->lock);
> if (status >= 0 && status != twl->linkstat) {
> status_changed =
> --
> 2.11.0
>

Thanks.

--
Dmitry

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