Nut upsuser - Jun 2011 - Restarting NUT twice in the same time creates 2 instances of usbhid-ups driver

Hello I'm new on this list, nice to meet you

My configuration :

OS : Ubuntu server 10.04.1 LTS
NUT : nut 2.4.3-1ubuntu3.1 from Ubuntu package
UPS : APC Back-UPS ES 530

My problem :
When restarting twice nut in the same time. I can see 2 instance of 
/lib/nut/usbhid-ups driver when using : ps aux | grep usbhid-ups

I know that's not normal to restart nut twice at the same moment but it 
can occurs on my system.

When reading /etc/init.d/nut, i see that when restarting nut, script 
stop nut and start it again.
When starting again the driver is one more time started without any 
verification that its already launched.

I think there is a problem in code there. have you a solution to bypass 
this problem without rewriting /etc/init.d/nut

Thanks

-- 
Rapha?l

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Le 23/06/2011 11:44, Rapha?l a ?crit :
> Hello I'm new on this list, nice to meet you
>
> My configuration :
>
> OS : Ubuntu server 10.04.1 LTS
> NUT : nut 2.4.3-1ubuntu3.1 from Ubuntu package
> UPS : APC Back-UPS ES 530
>
> My problem :
> When restarting twice nut in the same time. I can see 2 instance of 
> /lib/nut/usbhid-ups driver when using : ps aux | grep usbhid-ups
>
> I know that's not normal to restart nut twice at the same moment but 
> it can occurs on my system.
>
> When reading /etc/init.d/nut, i see that when restarting nut, script 
> stop nut and start it again.
> When starting again the driver is one more time started without any 
> verification that its already launched.
>
> I think there is a problem in code there. have you a solution to 
> bypass this problem without rewriting /etc/init.d/nut
>
> Thanks
> -- 
> Rapha?l
Excuse me, maybe im on the wrong list. I will try to post on dev list.


-- 
Rapha?l

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Citeren Rapha?l <raphael.broutin at ve-hotech.com>:
> When reading /etc/init.d/nut, i see that when restarting nut, script  
> stop nut and start it again.
> When starting again the driver is one more time started without any  
> verification that its already launched.
Stopping a driver is an asynchronous process. So you either have to  
check if the PID file is removed before assuming the driver has  
actually stopped or you need to wait a couple of seconds before  
(re)starting the drivers.
> I think there is a problem in code there.
This is an inherent effect of the method that is used to signal  
drivers to stop. On systems with multiple driver instances, you don't  
want to hang around waiting for a driver to actually stop before going  
to the next one.
> have you a solution to bypass this problem without rewriting
/etc/init.d/nut
The easiest fix is to add a delay between

    stop nut
    sleep 2
    start nut

Best regards, Arjen
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