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From:   Kristian Evensen <kristian.evensen@gmail.com>
Date:   Tue, 11 Sep 2018 16:34:18 +0200
Message-ID: <CAKfDRXgTL6L27JLbbOLLsXd9KK8vBtVCjrTNpv6R_MYCJoZqPg@mail.gmail.com>
Subject: Re: [PATCH] option: Improve Quectel EP06 detection
To:     Lars Melin <larsm17@gmail.com>
Cc:     Johan Hovold <johan@kernel.org>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Sep 11, 2018 at 4:00 PM Lars Melin <larsm17@gmail.com> wrote:
> This also becomes a mess for the qmi-wwan driver which has the rmnet/qmi
> interface hardcoded to 4 so that driver will also need a workaround.
> Quectel seems to have completely missed the reason why usb id's should
> be unique and not reused  for a different product or a different
> interface layout, there is already a workaround in qmi-wwan for their
> previous EC-20 card...

A patch has already been submitted to work around the issue in qmi driver.

> My opinion is that the option and qmi-wwan drivers should support EP06
> in the factory delivery configuration and not in a configuration the
> user has selected with a Quectel proprietary AT cmd.
> Can you give some good reason for disabling an interface instead of
> letting it stay but not use it if you don't need it?

Yes. I am working with two boards, one based on MT7621 and the other
on MT7623, and I would like to connect two EP06-modems to these
boards. However, the USB-controller used on these SoCs has a (very)
limited number of USB endpoints. With the default configuration, there
are only enough endpoints for one EP06-modem to work properly. By
disabling diag, there are enough endpoints for both modems to work
correctly.

BR,
Kristian