netdev - Re: hso: remove usb_driver_claim

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Date:	Wed, 10 Sep 2008 14:44:59 +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:
> Paulius Zaleckas wrote:
> Have you a hso device to test this on.
> If you have & it works it gets my blessing.

Yes, I have couple different hso devices.
This "usb_driver_claim_interface" patch was tested long ago,
but somehow I didn't post to the mailing-lists :)

I'll make patch for usb_driver_release_interface and
retest both patches.

>> 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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