From: "Bjørn Mork" <bjorn@mork.no>
To: Hayes Wang <hayeswang@realtek.com>
Cc: <netdev@vger.kernel.org>, <nic_swsd@realtek.com>,
<linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>
Subject: Re: [PATCH net] r8152: use cancel_delayed_work for runtime suspend
Date: Fri, 17 Oct 2014 09:42:02 +0200 [thread overview]
Message-ID: <87zjcvgn1x.fsf@nemi.mork.no> (raw)
In-Reply-To: <1394712342-15778-64-Taiwan-albertk@realtek.com> (Hayes Wang's message of "Fri, 17 Oct 2014 13:55:29 +0800")
Hayes Wang <hayeswang@realtek.com> writes:
> It would cause dead lock for runtime suspend, when the workqueue
> is running and runtime suspend occurs before the workqueue wakes
> up the device. The rtl8152_suspend() waits the workqueue to finish
> because of calling cancel_delayed_work_sync(). The workqueue waits
> the suspend function to finish for waking up the device because of
> calling usb_autopm_get_interface().
>
> Signed-off-by: Hayes Wang <hayeswang@realtek.com>
> ---
> drivers/net/usb/r8152.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 864159e..7d4e55a 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -3200,12 +3200,13 @@ static int rtl8152_suspend(struct usb_interface *intf, pm_message_t message)
> if (netif_running(tp->netdev)) {
> clear_bit(WORK_ENABLE, &tp->flags);
> usb_kill_urb(tp->intr_urb);
> - cancel_delayed_work_sync(&tp->schedule);
> tasklet_disable(&tp->tl);
> if (test_bit(SELECTIVE_SUSPEND, &tp->flags)) {
> + cancel_delayed_work(&tp->schedule);
> rtl_stop_rx(tp);
> rtl_runtime_suspend_enable(tp, true);
> } else {
> + cancel_delayed_work_sync(&tp->schedule);
> tp->rtl_ops.down(tp);
> }
> tasklet_enable(&tp->tl);
This looks strange to me. The delayed work will cause an immediate
resume due to the usb_autopm_get_interface() it starts with. Wouldn't
it be better to just prevent runtime suspending by returning -EBUSY if
there is any delayed work scheduled?
Bjørn
next prev parent reply other threads:[~2014-10-17 7:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-17 5:55 [PATCH net] r8152: use cancel_delayed_work for runtime suspend Hayes Wang
2014-10-17 7:42 ` Bjørn Mork [this message]
2014-10-17 8:55 ` [PATCH net] r8152: return -EBUSY " Hayes Wang
2014-10-18 3:46 ` David Miller
[not found] ` <1394712342-15778-64-Taiwan-albertk-Rasf1IRRPZFBDgjK7y7TUQ@public.gmane.org>
2014-10-18 19:48 ` [PATCH net] r8152: use cancel_delayed_work " Oliver Neukum
[not found] ` <1413661699.19391.2.camel-AfvqVibwNMkMNNZnWhT/Jw@public.gmane.org>
2014-10-20 2:19 ` Hayes Wang
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