From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Andreas Kemnade <andreas@kemnade.info>
Cc: kishon@ti.com, lee.jones@linaro.org, daniel.thompson@linaro.org,
wsa@the-dreams.de, linux-omap@vger.kernel.org,
linux-kernel@vger.kernel.org,
Discussions about the Letux Kernel
<letux-kernel@openphoenux.org>
Subject: Re: [PATCH RESEND] phy: phy-twl4030-usb: fix denied runtime access
Date: Mon, 17 Sep 2018 10:51:31 -0700 [thread overview]
Message-ID: <20180917175131.GA104770@dtor-ws> (raw)
In-Reply-To: <20180917052254.12336-1-andreas@kemnade.info>
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
next prev parent reply other threads:[~2018-09-17 17:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 5:22 [PATCH RESEND] phy: phy-twl4030-usb: fix denied runtime access Andreas Kemnade
2018-09-17 17:51 ` Dmitry Torokhov [this message]
2018-09-17 18:56 ` Andreas Kemnade
2018-09-17 22:23 ` Dmitry Torokhov
2018-09-18 16:16 ` Andreas Kemnade
2018-09-18 16:56 ` Dmitry Torokhov
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