netdev - Re: hso: remove usb_driver_claim

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Date:	Wed, 10 Sep 2008 13:34:17 +0200
From:	Denis Joseph Barrow <D.Barow@...ion.com>
To:	Paulius Zaleckas <paulius.zaleckas@...tonika.lt>
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()

Paulius Zaleckas wrote:
Have you a hso device to test this on.
If you have & it works it gets my blessing.

> 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:
>>


-- 
best regards,
D.J. Barrow
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