netdev - Re: hso: remove usb_driver_claim

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Message-ID: <48C7AEDC.8060902@teltonika.lt>
Date:	Wed, 10 Sep 2008 14:26:20 +0300
From:	Paulius Zaleckas <paulius.zaleckas@...tonika.lt>
To:	Denis Joseph Barrow <D.Barow@...ion.com>
CC:	linux-usb@...r.kernel.org, netdev <netdev@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: Re: hso: remove usb_driver_claim_interface()

Denis Joseph Barrow wrote:
> Hi Paulius,
> I'm not in a position yet to know if this patch is good, yet at least.
> hso_probe gets called once for each serial ttyHSx device
> usually four per usb stick modem & once for the hsox network device
> per modem.
>  
> From the comment on usb_driver_claim_interface
>  * This is used by usb device drivers that need to claim more than one
>  * interface on a device when probing (audio and acm are current examples).
> 
> I'm not used to USB terminology
> From my understanding of the code
> we are claiming more than one interface on the usb modem multiple ttyHSx devices
> & one network device. However we get probed once for each interface

usb_driver_claim_interface() is needed only when you want to claim
additional interface.

> We are also calling usb_driver_release_interface from hso_disconnect.
> This looks a little asymmetrical to me.

Nice catch. usb_driver_release_interface() is not needed there too.
This is some code from usb_driver_release_interface():

         /* don't release from within disconnect() */
         if (iface->condition != USB_INTERFACE_BOUND)
                 return;

So since hso_disconnect is usb disconnect(), function call to
usb_driver_release_interface() just returns without any action.
I will prepare patch for this one too.

Greg: Maybe we should put warning in this check to catch other
driver from misusing this function?

> Greg is this patch good? I've no problem with it if it gets your guys blessing.
> 
> 
> Index: linux-2.6/drivers/net/usb/hso.c
> ===================================================================
> --- linux-2.6.orig/drivers/net/usb/hso.c
> +++ linux-2.6/drivers/net/usb/hso.c
> @@ -2487,8 +2487,6 @@ static int hso_probe(struct usb_interfac
>  		goto exit;
>  	}
>  
> -	usb_driver_claim_interface(&hso_driver, interface, hso_dev);
> -
>  	/* save our data pointer in this device */
>  	usb_set_intfdata(interface, hso_dev);
>  
> 
> 
> 
> Paulius Zaleckas wrote:
> 
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