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Subject: Re: [PATCH 3/4] USB: serial: add support for multi-interface
 functions
From:   Oliver Neukum <oneukum@suse.com>
To:     Johan Hovold <johan@kernel.org>
Cc:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Thu, 08 Apr 2021 12:10:48 +0200
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Am Donnerstag, den 01.04.2021, 09:46 +0200 schrieb Johan Hovold:
> On Wed, Mar 31, 2021 at 01:21:15PM +0200, Oliver Neukum wrote:
> > Am Mittwoch, den 31.03.2021, 09:08 +0200 schrieb Oliver Neukum:

> > on the third hand, the more I look at this, would you mind putting
> > sibling_release() with a modified name into usbcore? This functionality
> > is not limited to serial drivers. btusb needs it; cdc-acm needs it;
> > usbaudio neds it. We have code duplication.
> 
> Tell me about it. ;) Unfortunately, drivers all tend to handle this
> slightly different, for example, using a disconnected flag, some claim
> more than one other interface, others look like they may be using their
> interface data as a flag for other purposes, etc.
> 
> At some point we could unify all this but until then I don't think
> putting only half of an interface into core makes much sense.

OK, very well, then let's look at this from a fundamental point
and design a bit. First, can we disregard the case of more than
two interfaces?

	Regards
		Oliver