Hayes Wang <hayeswang@xxxxxxxxxxx> 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@xxxxxxxxxxx>
> ---
> 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
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